IPB and Xenforo vs MyBB

MyBB is literally one of the best forum softwares you can use. Lots of people use it, so there will be support no matter where you go, and it is VERY customizable, thanks to mods, themes, and the ability to change templates and such.

I will note, though, that MyBB has a bunch of security vulnerabilities, and that you should at least have some knowledge about HTML or CSS.

All in all, you're making a very good decision to move to MyBB.