The XPlay is a brand-new device, so second-hand ones are going to be a bit hard to find. And it's not quite fair to try to compare it to a 2-year old phone, either. It's pretty competent, and if you want to game on a phone, it's hard to beat.
That being said, UAE4Droid is pretty poor. Playstation emulation, on the other hand, is quite good on the Xperia Play.