I am still trying to figure out which one will be my real "phone." I like the bigger screen on the e62 but the functionality on my 8700c is awesome. I like using Google Maps, etc., without the hassles from the device asking me about permissions. ... (Thanks, Cingular.) The e62 feels like a brick when I use it as a phone but I have signal problems on both devices when I am outside. ... Go figure.
It's too soon, I think, to make a decision on voice quality.
I deleted BB Connect on my e62, given that I have BIS on my 8700c. I now have XPress Mail on there. My e62 also has a regular Media Net plan since I don't use it to connect to the Web anymore. (We use my wife's 3G Samsung A707.) [I use BB Unlimited on the 8700c.]