Battery life on the 520 is pretty great. Lasts 3 days easy.

The dual-sim 630 just came out in India [0], but the price appears to be closer to $200. It has a 4.5" gorilla glass screen, but keeps the 512MB of RAM, and has no LTE support (that's in the coming-soon 635).

See my other comment on this thread for thoughts on how a 512MB WP device might provide a better long-term experience than a 1GB Android device in some ways.

I find this low-end market fascinating. Personally I use and prefer a Nexus 5, but as a WP developer it's eye-opening to see that fully 50% of our active WP8 user sessions are on a 512MB WP device (and almost half of those are 520/521).

[0] http://www.ibtimes.co.in/nokia-lumia-630-india-price-reveale...