With the built-in speakers, it's almost a PX-S1000 on steroids (well, not really).
I'd say the closest Casio competitor is the same-priced PX-560, in terms of being a full-featured lightweight stage piano with speakers.
Each has some significant features the other does not. Roland has much better MIDI controller functionality (including Mainstage integration), and when it comes to splits/layers, you can put independent insert effects on three parts (vs. only one part being able to have its own effects on the Casio), and it includes VA synth capability (PX-560 lacks even a monophonic synth mode). Casio advantages include more split/layer parts (4, which can even be extended to 24 with hexlayers, whereas Roland is 3), full on-board sound editing (it looks like the only deep editing on the Roland might be to own another zen-core board that has editing), and built-in sequencer. If you want a versatile lightweight weighted 88 with speakers and lots of sounds, with a live-friendly interface and standard MIDI connectivity, I think these are the two to look at. I'll be curious to see comparisons in their sounds and actions.