Yes, I've seen a few users around the forums, that did just this. If you're going from the 1520 to the 930 then battery life will be an issue. Screen size and speed will also be an issue..
All I can say is, it will just take some time to get used to these issues and after that they won't even be issues lol
I started by saying that I've seen users around the forums jump from one to the other. The fact that I started with that statement seemed (for myself) enough of an indication that whatever comes after that would be what I saw from them..
The issues with speed and battery life are not drastic (you won't wait for 30 seconds, but 3-5 seconds). Some make a big deal about those few seconds.
Again, after saying that speed and battery life might be an issue, I made sure to add that some users make a big fuss about it, so again, it wasn't based on my own judgement (and I also wanted to note that I mostly disagreed with the notion that people wanted to compare them so much)
Edit: All in all, I know that many 1520 users would tell anyone that was wondering if they should ditch the device, even though it's running without any problems, that they would be insane to do so. The only reason to leave the 1520 behind at this point is simply, the size..
Keep in mind that I also pointed out that the 930 is a great device, because I have personally played around with it for a few days