I'm newer to android. Got my ASUS tf 700 this summer and now I'm going to android for my handset. I'll be moving to Straightalk prepaid and they offer a galaxy s2. I've been watching google shopping, amazon etc for pricing to get an unlocked s2 but have found many different varieties (skyrocket, gt 19100 etc) What do all the types mean? will 4.0 be available to all of them?