Don't rule out the 525 too quickly.
525
1 GB RAM, meaning more games (which some complain about on lower RAM devices, ugh all those Subway Surfer threads...)
Camera button
4" display, its smaller, but sharper, perhaps not as deep blacks as the 630
actual soft buttons on the front, not lit however
630
More cores, but not too big of a difference?
Virtual buttons, comes down to personal preference I'd say
No camera button
harder to find batteries, but the battery is much larger
Larger 4.5" display but isn't as sharp, supposedly better, but I can't say.
No rumor for anything else, if you can pick up a secondhand/older device, like a 620, it probably is a good option.