Buying my first Windows Phone! Don't know which to pick, pls help..

Hello, I've been lurking on this subreddit for a while as I've wanted to get a Windows phone for about a year now. My network is AT&T and it looks like my two main options are The 830 or the 1520. I've taken a look at both of these phones and I can't seem to decide which to pick. I like the 830's size better but I also see that the processor and ram is clearly better on the 1520. The killer here is that I would probably be paying the same price (even though the 830 comes with a fitbit) for either of them so I'm pretty lost.

Do people on here that own these phones have any advice that would help me pick? Thanks so much!