What does AnyDesk do well? AnyDesk is probably the lightest and most native-like remote desktop solution I've used for Windows besides Microsoft Remote Desktop (which I suspect will always be my preferred method). I love how easy it is to use, which makes it ideal for supporting users outside the network. Just have 'em download it (it's very clear on the website), then get their code and you're ready to help!
What does AnyDesk not do well? I don't really have any complaints. It can lag sometimes, and do weird thing with graphics, but that's the case with any of these that are essentially reproducing a display virtually.
What do you wish you had known about AnyDesk before using? AnyDesk is simple to use, maybe one of the simplest solutions besides Chrome Remote Desktop. It's not as full-featured as TeamViewer, but it's much more lightweight and can even be run without a full install.
Have you used a competitor to AnyDesk? If so, how does it compare? I've used a wide variety of remote desktop solutions, mostly on Windows, from Microsoft's native one (my go-to whenever possible), to Teamviewer or Chrome Remote Desktop. I'd say that these all have their purposes, with Microsoft RDP being the most full-featured, then Teamviewer, and Chrome and AnyDesk being the simplest to use, and especially simple for users who don't know what they're doing. Chrome of course is limited to use in Chrome, so AnyDesk overcomes that barrier.