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.
WaveLab is well-suited when you want to apply a lot of VST FX processing to audio, or do a real-time recording and be able to hear how the FX processing sounds as you're recording. It is an excellent tool for recording in the studio. However, it lacks the sophisticated multitrack capabilities you find in a Digital Audio Workstation (DAW), instead of focusing on the features of an audio editor. It is also great for quickly opening, editing, and saving a lot of files because of how fast it is.
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.
Realtime FX Chain - This is the big one for me. I always had both WaveLab and Sound Forge (along with some other audio editing programs, and using Pro Tools at school). Of the two, I preferred Sound Forge for its user interface and hotkeys, but I preferred WaveLab for its realtime FX. The ability to easily chain FX together and tweak them on the fly while the audio is playing is enormous for me.
Speed - Quite simply, saving a huge file in WaveLab is orders of magnitude faster than in Sound Forge. To this day, I don't know why that is, but it's just faster. Opening and saving files is a breeze in WaveLab, while in some other audio editing programs, it can take 30 seconds or a minute for a large file.
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.
User Interface and Hotkeys - I've always struggled with the UI in WaveLab, and even after all these years, I am just much faster in Sound Forge. I used to have a job as an audio editor, where I edited hundreds of hours of interviews. By using the "Mark" feature, I could easily cut out silence, "ums" and "ahs," and other audio artifacts in Sound Forge. I struggled to do the same in WaveLab but was never able to work even a fraction as quickly.
Built-In Audio Processing - I much prefer Sound Forge's built-in audio tools like time-stretching, normalization, compression, and so on. WaveLab has many of the same tools, but I have not found them to be as easy to use, and in some cases, nonexistent (relying instead on a VST plugin).
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 have never contacted Steinberg, so I am not sure how responsive they are. Still, I've watched countless tutorials on audio editing and mastering in WaveLab, so I am pleased with the level of support available from the online community of users. It is a much-loved program among audio industry professionals, and there are all sorts of great tutorials, tips, and tricks available online.
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 am relatively agnostic about what audio software I use. I still use WaveLab to this day, 21 years later, for applications where I want to apply effects chains and tweak them in real-time. Sound Forge even can't do this for some reason. But when I have a lot of editing to do, I'll typically open Sound Forge instead, because I prefer the workflow of using the "M" hotkey to mark the audio as it's playing, and then quickly skip through markers and edit out audio artifacts. When I'm recording a vocalist, however, if I am not using a Digital Audio Workstation (like Ableton Live), then I do prefer WaveLab. I can apply VST effects in real-time to the audio coming in through the sound card input and playing back in their headphones.
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.