I like the new SIP. Matches better with the HTC Dialer. I always was of the opinion, the SIP should match the dialer. More aesthetically pleasing overall when the buttons you press remain consistent.
I've used UltraLite for about 2 weeks, I'm tempted to go Groove5. Logic keeps telling me to "if it's works, don't change it" but my ROM fix is saying "do it!".