It's funny how different people with the same phone are having such different experiences. It must be a matter of what different apps each person has installed, that's the only wildcard.
For example for me Beta 5 has been an absolute dream, I haven't experienced a single respring and no issues with imessage *knocks on wood*. And all of my issues that made Beta 4 and absolute nightmare have been fixed (unresponsive screen with brightness down, Apps not updating, podcasts not downloading, netflix not downloading, etc...)
I almost want to stay on beta 5 and not move until release since its been so great (although I dont think you could do that, I seem to remember betas expire or something)