Where to begin! I think if I had to pick one thing, it would be that they have the strongest most consistently clear connection of any video calling software I've tried (and I've tried a ton). Even if myself or my client are working from 1mbps or less, I know I can rely on their quality.
Uhm.....nothing! Honestly they are my go to for everything business related, and I've even used them for important personal calls because they are more reliable than other options.
There is a free plan, give it a try! You don't need to decide based on faith, they'll show you why they are the best.
Zoom allows me to work with clients all over the world. Without them I wouldn't feel as secure scheduling with someone in Australia or Bolivia...or even Oklahoma, when I'm somewhere completely different. They truly bridge the gap so it's as though we're in the same room at the same time!