The PXS is the sleekest of the portable arranger pianos (25 lbs vs Yamaha DGX670 just over 47lbs, Roland FPE50 just under 38lbs, not to mentino the PXS3100 is half the depth *and* thickness of the DGX)
*however*:
The piano on the Casio is pretty decent; since the FPE50's is modelled (ie not a sample, but synthesized) so a lot of people will find the FPE50's piano sound ''hollow" and the worst of the 3; Debatable if the DGX's is better on headphones, but the DGX has fuller sounding speakers than the PXS, so for me it wins there. The FPE50 has the beefiest speakers by far of the 3; the DGX's are in the middle.
The PXS's keys are the shortest and worst of the 3 (but as long as you play on the keytips, not halfway up the keys, I find it perfectly playable still). But I'll still take both the DGX and FPE50's keys over the PXS's.
The arranger is where it gets dicey; the PXS is definitely the most difficult to navigate. The DGX is a hair easier than the FPE50 to navigate, but the Yamaha and Roland are quite easy to navigate. Only the DGX offers Karaoke functions (scrolling lyrics on screen with compatible midis, and the ability to record all of that plus blue tooth audio input onto a USB stick. The FPE50 offers the same minus the lyrics, the PXS doesn't have a mic input or mic DSP's).
The PXS is the only one that can run on batteries (6 x AA).
This may come as a surprise, but for acoustic guitars & pipe organs, I'd put the DGX at the top and the FPE50 at the very bottom of the 3 (and Roland designed the styles around that limitation; avoiding acoustic guitar strumming in most styles, but when it is present it's pretty cringey). Roland has the best drums of the 3, powerful and punch. Casio's drums are pretty good *except* the default style (Bruno Mar's 24 Karat) using a *very* shrill drum kit, so much so that if you have it at full volume, and accidentally start the default style, your ears will hurt. The other styles sound *great* (Billie Jean, Moves Like Jagger), so I'm not sure why they chose that as the default .
DGX is the only one I know where you can output the style as midi data; the FPE50 only has a single channel midi out! that means the Roland will literally only send your keypresses literally all to channel 1; no way of grabbing any info on the styles or even sending out left hand split to another channel, rendering the midi functions almost useless on it. PXS is slightly better with 2 channels midi out on the right and 2 on the left, but AFAIK no way to grab the style info as midi either. DGX by far has the best midi implementation of the 3, will full multi midi out, separate channels for each style part and Right1,Right2, Left, as well as the only one where you can create styles on board and import new ones easily.
I don't think the Casio even allows importing; the Roland sort of can through Roland sound cloud, but obviously that's exclusively Roland's own (very well programmed if you want 80's pop/rock, modern pop, hip hop, R&B) styles. DGX has literally tens of thousands of styles available to download online.
HOWEVER the DGX is also the only one lacking proper line outs! (although you can record lossless audio internal via USB flash drive).
Sorry, I know that's a lot. Like Biggles said, nothing beats trying them hands on.
But in a nuthsell:
Category........Best...-..Mid - Worst
Keys················DGX ~ FPE >> PXS
Speakers········FPE >> DGX > PXS
Piano sound··DGX > PXS ~~ FPE (all 3 decent)
Midi out·········DGX>>>PXS > FPE
Ease of use····DGX ~~FP >>>PXS
Mark