We used it company-wide, but engineering did not adopt it due to compatibility issues on their systems. We frequently communicate with remote customers and colleagues located outside of our main office and needed a way to facilitate reliable video conferencing. We make the most use of the audio and screen sharing functions, though the video function is also used too.
Generally well-liked among the business side of the company. Engineering did not like the installation requirements and found that it was susceptible to problems on some APs (I didn't see this problem).
The free plan is usually OK, but it would have been better to have had a coordinate business account that allowed centralized billing and a few more user management features. We just couldn't afford it for all users.
Zoom is definitely your choice if you value video in your conferences. There are simpler options if all you want to use is screen sharing and VoIP audio.
I've generally used Skype less and less over the years... the main reason to do so is that I find the other party uses a different system than me, but we both have Skype accounts. The address book that I've built over the years is probably the main reason that this app is sticky.
You can't beat the simplicity of UberConference -- and no plugins to worry about. However, you have to use Chrome (at least on MacOS) if you want to screenshare. It generally seems to be pretty robust on low bandwidth networks... but it can't use your camera.
GoToMeeting is a fine solution... I generally preferred its UI conventions, but found that is behind Zoom with respect to video quality.
Google Hangouts are particularly good if you are using the Google apps for your business -- the integration is helpful.
Net-net, Zoom is really the leader when it comes to multi-party video... their quality is impressive, but it's not the most important feature for me personally.
Zoom is a solid video conferencing solution for most small organizations. Depending upon the price point, you get features that make it easier to deploy and manage across a large organization. Most startups would probably pick the free "Personal" plan, but keep in mind meetings are limited to 40 minutes. We actually used this as a way to force our meetings to be shorter -- the deadline was helpful. If you need more than 100 participants or more advanced user management, you'll need a paid plan.