I still have my prs 650. A friend owns the t1, I liked the wifi, as she can read manga directly from websites, or load fanfictions and the such. I own a tablet so it's no biggie, but I can see why some people would like the upgrade.
I don't see myself changing it anytime soon, It does what its intended to and it does it well. I have a couple of hundred books in it in the 2+ years Ive had it, and has never let me down. Battery seems to be doing ok, too. I even use a waterproof case and take it to the beach and the pool
(Mostly for water/sand protection, I rarely go IN the water with it). The spine in the case broke a while ago, I'm looking into home made solutions, but the light is doing ok. A couple of pixels in the screen look dead (and the ink spread out like a little spider), but its very small.
best toy for a bookworm like me