For the most part, it doesn't matter if you get GSM or a VZ Pre 2. Either will work. (Edit: It will matter in terms of which meta doctor script you use, though.)
Originally Posted by Shadowcat
A VZ Pre 2 is preferred as the length of the antenna cables that go to the com board is the same, so everything fits better. The GSM version has longer antenna wires you have to tuck in.
I've been noting to folks lately that if you use the pictorial wiki page for the upgrade process, it isn't pictured that you can remove just the com board from the back bezels by disconnecting the black/white antenna cables. They plug/unplug just behind the metal shield where those two cables go to the com board. You can (gently) pry up the shield right there to get to the connection, no problem.
Kinda important thing to know if you want that shiny new back bezel with its fresh buttons and headphone jack!