We use Zoom for collaboration and conferencing with several partners. I've found it to be an excellent solution in this very crowded space. One of my favorite things about Zoom is that I feel it has all of the features I want and need without a bunch of extra junk i will never use.
One of the things I think Zoom does very well is the VOIP feature. I have several different audio peripherals on my PC and many solutions I've used seem to struggle when selecting/switching between them. So when I discover a solution that works well it makes an impression.
I find Zoom's feature set to be spot on. It has everything I need in a simple user interface. But it leaves out things that I'd likely never ruse and clutter up the UI.
I've used many other collaboration solutions, primarily WebEx. It is very feature-rich, and has the price tag to go with it. For some companies it probably makes sense. But for probably 95%, Zoom has all of the features they'll need at a very good price point.
I feel that Zoom is an excellent solution for SMB, and small enterprise. It could even be great for medium and large enterprise, but I feel there are some features WebEx brings to the table that make sense at that scale.