Used my $10 coupon, and got it for $39.99.
I know, I just spent about $40 to upgrade a Lumia 520 to another 512MB device. However, I am actually quite happy with the upgrade. Bigger screen, which with my short fingers is the maximum size I can handle in my hand and still work one handed. Well, somethings I need 2 hands to do, because I can't quite reach the entire screen area like I could on the L520.
However, the big upgrade part for me is going from not having LTE compatibility to having LTE. Since the primary reason I bought a smart phone was to use as a hotspot for my laptop, then that made it worth the upgrade. Much faster page loads. I can tell a big difference. According to the speed tests I ran before and after the upgrade, I have actually improved my UL/DL speeds by approximately 6 times over what I had before. I'm happy.
I'm really, really happy with the 635. The Quad core over the dual core actually makes a good bit of difference for the things I do on the phone. I don't play games other than Solitaire on the phone, and that's extremely rare, so mostly just use it as a phone, Bible, camera, MP3 player, and simple things like that. Sure is a difference on camera load time, though. Not as fast as a 1520, but fast enough for my modest needs.
Thanks for this thread and the heads up on the price. Never would have bought it otherwise. Had just enough cash given to me for Christmas that I could spring for this and a nice case for it.