I really dislike the .607 build from Verizon. It has locked up on me and my fiance's phone a lot, both are 9550's. The keyboard in bbm get really cumbersome. I was using the .517 from sasktel that I downloaded from here. it worked fine I think but Not sure i had it long enough to really play with it. None the less, I don't want .607. What's everyones thoughts on the best build for the 9550?