Alex, thanks for getting the thread off to a good start.

I'll give an example of my own.

Maestronet

Pros: It is prettier than Mudcat. The multiple forum idea seems to work. It is easy for me to avoid the forum called "The Soapbox" so I can focus on the mostly music threads in "The Fingerboard." The users seem to do a good job putting threads in the appropriate forum.

Cons: The prettier format makes browsing a little less convenient than Mudcat. I find it easier to scroll down a list that to click on a "next page" icon. I am not happy about having to register to contribute to the forum. The fact that it has a commercial affiliation makes me a little suspicious.