ACID Pro is great for electronic music, hip hop, and any loop-based music production such as for videogame soundtracks. It is great for audio-forward production, rather than MIDI-forward. If I were running a lot of hardware synthesizers, or even softsynths using MIDI, I would prefer another DAW since they often have better features, for instance in the shuffle department where Ableton Live has hundreds of shuffles to choose from for MIDI instruments. However, I still prefer time-stretching sound quality in ACID Pro, as well as the lack of audio artifacts in looping. To this day, Ableton Live has still not entirely figured out how to prevent clicks and pops at the beginning and end of loops, especially lower frequencies like basslines, without shaving an arbitrary amount of time off each side (.5 ms by default), resulting in lessened attack and audio artifacts during cuts. I feel that ACID Pro has a better audio engine for looping, although for many purposes this is not noticeable. Still, I prefer ACID Pro for wave-based (rather than MIDI-based) music that makes extensive use of loops.
Sound Forge is great for when you need to edit a lot of audio, like interviews, spoken word, podcasts, monologues, presentations, lessons—you name it. When you have a lot of audio to get through, Sound Forge can make it go by very quickly by using such features as the markers and hotkeys for normalization, inserting silence (where needed), graphical fades to remove audio artifacts, and so on. I've been able to edit a 1 hour interview in 2 hours, having made hundreds of edits in the process. Sound Forge is less useful for situations where you want to hear a realtime effects chain, or record with VST effects on. For instance, if you want the person being recorded to hear their own voice through headphones with reverb and compression applied, I do not know how to do this in Sound Forge. I think it is impossible, but even if it is possible, it is not readily apparent how to do so.
Audio sequencing: It's great for those who like to work primarily with waveforms, rather than MIDI.
Loop-based sequencing: It's perfect for loop-based music.
Envelopes: It's quite easy to do things like volume fades, crossfades, and other envelope-based audio manipulation of the waveform.
Time-stretch: ACID Pro has nice time-stretch filters.
Multitrack nondestructive sequencing: I like the UI for multitrack, and how easy it is to get back to a previous state through undo history, even copying something from a future state and then undoing a number of steps before pasting in the later content.
Markers - You can rapidly edit spoken audio to remove pauses, "ums" and "ahs," by using the marker feature while listening to the audio in realtime. Then, you go back and cycle through the markers and make the edits very quickly.
Hotkeys - Once you've learned the Sound Forge hotkeys, you can rapidly perform a number of tasks related to audio editing and mastering.
Fixing Clicks and Pops - The Graphical Fade feature allows you to easily draw volume envelopes in extremely short spans of audio, to successfully remove clicks and pops without affecting the rest of the sound.
Organizing VST Plugins - Sound Forge has a nice way of organizing VST effects into folders so you can put your most regularly-used plugins in a "Favorites" folder while organizing others in a sensible way.
MIDI: I don't think it is great for MIDI sequencing. There are much better piano rolls and software step sequencers out there.
Built-in effects: ACID Pro has not kept up with competitors like Ableton Live, who licensed Cytomic's Glue Compression for version 9 of their software, an incredible-sounding plugin that would otherwise cost a pretty penny but is now included for free in Live. That being said, I haven't used it but I see they are making strides in this area, with new versions of ACID Pro including third-party licensed effects like Zynpatic STEM MAKER 2 out of the box for free.
Live performance: ACID Pro still doesn't hold a candle to Ableton Live in this department.
Improvising with loops: Despite recently added features like the ACID Morph Pads, the Chopper, and the revised Beatmapper, which allow MIDI triggering of parts of samples as well as creating new sounds using raw audio as an input, I feel that ACID Pro has a ways to go before they harness the improvisatory power you get with something like Stutter Edit, or the performance features of Ableton Live.
Batch Processing - While I like a lot of things about the batch audio processing in Sound Forge, the inability to hear the effects chain is limiting.
Performance - Sound Forge takes a long time to open large files the first time they are opened, as it draws the waveform. It also takes a long time to save large files, every time.
Inability to Listen to VST FX in Realtime - Technically you can listen in realtime, but only from the beginning of the waveform, rather and it is not easy. You have to open the VST effect and turn on the "Preview" mode which starts the audio from the very beginning, without being able to seek.
Inability to Chain VST FX - You have to apply one, then apply the next, then the next, in a destructive mode. The only non-destructive way you can test out different FX chains is by applying them one at a time, and then hitting "Undo" over and over to get back to an earlier state. But you couldn't, for instance, add a reverb, then add compression, then go back and change the reverb. You'd have to undo the compression first.
FX Preset Management - You can save FX presets but it does not save your last-used settings from session to session, and with some VST FX plugins, it doesn't even save them between application, undoing, and attempting to apply again.
ACID Pro was the first loop-based DAW I ever used, and I fell in love with it. I was an avid ACID Pro believer for many years, before making the switch to Ableton Live as my primary DAW. Even still, I prefer the sound quality of ACID Pro in many cases. Ableton Live just "sounds" like Ableton, and there are audio artifacts that annoy me. I have been able to work around many of them, but I still have a special place in my arsenal for ACID Pro and use it whenever the chance arises, typically for loop-based wave-heavy music that doesn't need to be performed live and doesn't have a strong reliance on MIDI sequencing.
I've never contacted MAGIX for support, nor Sony or Sonic Foundry before them (Sound Forge is on its 3rd developer now). But I've always been able to find exactly what information I needed through the support of its large user community. There are a number of audio engineering forums available where you can search the post history to find out how to do specific things in Sound Forge, or you can make a new post if you are running into an issue that has not already been solved.
Due to my history as an audio engineer and having worked at many studios over the years, I've been exposed to a wide range of DAWs from Pro Tools, Cakewalk, and Nuendo to Reaper, Max/MSP/Jitter, and Processing. (These latter two are not really DAWs, per se, but rather systems that can be used for programming audio production — Reaper has features like this as well.) I point this out simply to say that I have experience with a wide range of DAWs and am fairly agnostic about them. I certainly have preferences. If I'm working with an indie rock band or a singer-songwriter, I like Pro Tools, since it is an industry-standard. For hip hop or electronic music, I prefer Ableton Live or ACID Pro, since they make working with loops so much easier, and I believe the sound fidelity is better. I choose ACID Pro specifically for loop-based music which almost entirely comes from waveforms rather than MIDI instruments (real or virtual). I find ACID Pro's MIDI functionality lacking, but the ease of sequencing and working with loops more than makes up for it.
I tend to use WaveLab for recording, because I can apply effects chains to the audio as it is coming in. So, if I'm recording a singer, I can give them reverb, compression, EQ, and other audio effects in realtime going into their headphones. I'm still recording the dry signal, so I can change all of those effects later if I wish. Sound Forge does not have a way to do this as far as I know. Where I do prefer Sound Forge is audio editing, specifically of spoken audio, although it is quite useful for music as well. I worked for a company once where I had to edit hundreds of testimonials. I was paid on a per-testimonial basis, flat rate, so I had a strong incentive to get them done as quickly as possible, without sacrificing quality. I would listen through a testimonial all the way through, marking every area that had a long pause, an "ah" or an "um," a click, pop, or other undesirable audio artifact. I could then cycle through the markers and fix all the problems quickly.
Positive: Easy to use. Up and running in minutes. Virtually no learning curve, just drag, and drop.
Negative: Limited in its improvisatory and live performance. This has not made a negative impact on the business per se, but can be a creative block when you are trying to come up with a music bed or interstitial and want to experiment with mixing and matching different loops. There's no easy way to do this on the fly in ACID Pro, as there is with Ableton Live.
Positive: ACID Pro now includes more effects than ever, ameliorating the need to purchase plugins.
Sound Forge has had a very positive impact in saved time editing files. It would have taken me hours longer using WaveLab, Audacity, Adobe Audition, or some of the other competitors for tasks like editing interviews.
Sound Forge has also had a positive impact in saved time through its batch processing features which allow me to normalize and apply effects to a huge set of files all at once.
Sound Forge has not had any negative impacts that I am aware of beside the cost.
