Build 3 was good for me the day I installed it when it was released. And then surprisingly, the performance started to degenerate. I did not observe this phenomenon in the previous 2 builds. So, today, the iPod function decided to give up on me. Plugged into iTunes, and there was a syncing error. The information in iTunes' iPhone "info" section indicated that the songs were present, but iPod app failed to detect any songs present when the app is launched.
Did a clean restore and its all good again. Snappy SMS, minimal delay in transiting between functions. So I'm just going to observe again if this is an isolated incident or a repeat occurance.