You might have already bought something, but...
As Mike indicated, it depends on what you want to use it for. As a pianist, my primary concern is the sound, and I can tell you from experience, Peavy & Behringer don't make the grade; sure, they're inexpensive, but you won't be thinking 'bout that 6 mos. from now. I still have a Peavy, but only use it as a stage monitor, and line out to an effects processor and ultimately, the board; alone, it just doesn't sound like a piano. Behringer ranks down there w/ Crate, and the specs are misleading--if it says '2-channel, 30w' that really means 15w per channel--you'd need to do some manipulation to actually get 30w. IMO, both Behringer and Crate are for folks who just don't know any better.
Never tried the one Talbot notes, but have tried Fender before and they're not bad...but not my first pick. I prefer Roland, Hartke and, if you can find one and don't mind spending a bit more, Motion Sound. Both Roland & Hartke offer a range of specs and you can find 'em used for <= $400 (I seldom buy new myself). Roland & Hartke are the gold standard, as far as I'm concerned; I have a KC350 I picked up used, have never had any issues w/ it and it sounds like a piano. (Of course, your DP has a lot to say about this, and I'm not familiar w/ the Casio you mention--I use Roland & Korg. From what I'm reading, it sounds like the XW-P1 is more a synth than a piano, so...)
I like Motion Sound because of the mech. rotary speaker system and spatial expanders--they come as close as anything I've ever heard to true Leslie emulation, and like the Roland & Hartke, they sound like a piano--or whatever you're feeding through 'em. They're not a big seller due to poor marketing and price (new units are very pricey, comparatively), but I love the sound. I've seen used ones for ~$400 - $600, but they're not easy to find on the used market. Pro's tend to hang on to them.
But I play mostly jazz/jazz-oriented music, and that likely isn't your thing (judging from the Casio XW-P1 purchase); YMMV. Still, for me, the bottom line is the sound coming out of the amp. Hope this helps.