Just wondering how everyone decides who's build to use. If you go to the developer section of the forum you have about 10 guys all actively releasing their own builds. I have always just used the most recent updated build from the download page off the main dolphin site.
When should I be looking at other builds and such?
1- Always use Dolphin 3.0 it's the official release
2- If you want recent builds and if it isn't on the DL page try this site : emucr.com
3- To choose your build there's often a description of what's new/what's been added so it can help
4- If you're searching the best build for a game in particular go into the thread dedicated to this game if this thread exists of course
The lord pretty much sums it up.
To be honest, I've never noticed huge differences between builds and whatever performance optimizations can be made will not result in huge benefits. If there's something in particular you need, check game-specific threads as mentioned above.