I run grooverom 5 and the updated sprint radio with htchome2 as my today screen. I think it's pretty simple, fast and powerful, but it all depends where you live in terms of radio and also your carrier. If you want simple, maybe go with indagroove's simple rom. I haven't tried it, but based on Inda's work, I'd say it's probably rock solid considering it's 6.1 and simple. Check the radio thread for your location
http://forum.ppcgeeks.com/showthread.php?t=56611