Which is the best forum plugin ?
bbPress or Simple-Press ?
- The one that suits the best to your needs/ requirements.
"The best" doesn't need to be the same for various persons.
BTW, more people are telling good things on bbPress which doesn't have to mean that it's better then SimplePress or any other Forum plugin.
- Another one to check out: https://muut.com
- Without knowing what features and functions you need, it's impossible to say which is "best" for you. And it's easy enough for you to read the feature set of each and decide.