here is the link to check out the case swap from cdma to gsm this will also explain the difference in these cases :
http://forum.ppcgeeks.com/showthread...ght=white+case
As for all cases being plastic you are correct they do only have a rubberized outside, but those cases that are rubberized last longer then those that don't and that's a fact. Verizon's cases cracking is a known issue and has its own sticky at the top of the page.