Lime Survey. I needed a self hosted solution and after a long search and evaluating a lot of alternatives, finally settled on this because a lot of advanced features were needed.
Pros: all possible features that you could need and a lot more. Admin interface is very powerful. Easy to install, extend. Cons: PHP. Complicated (as it’ has a lot of options). Scripting language is a pain in the butt.
There’s this one Bluetooth speaker with a microphone that I have, that I had hoped to use for calls, that has just refused to work. Spent hours trying to get them to work but had to admit defeat. But yes, things have improved significantly.