I can see right now having the 16 gb model (which I have) for the 1520 could pose as a problem if its not enough storage space for you, but I'm pretty sure that I read correctly that with windows phone 8.1 they will let you install apps onto a micro sd card, so since the phone can take a micro sd card, why bother with the 32 gb model? AND YES, I do realize that putting external memory into a phone is slower, even when you use a class 10 card, but its not that much slower, and especially when I can buy another 16 gb card for like 10-15$ I personally wouldn't pay an extra 100$ for it, just my 2 cents fyi.