Yam PSR 1500-piano(which is regular) -more or less same as their new 200$ psr 29X series.not as good as dgx 305,505(which have LIVE! warm grand).
but the good news in 1500 is it has same simutaneous EFX like 3k so you can EQ it to get relatively acceptable piano sound.
now PA50.(the difference between 50 and 60/80 is unlike 60/80(where keys are like previous models- IS 40,50 series),PA 50 now has different key feel.it's still no AFT sensitive(like psr 1500 or 3K)but key feel is more predictable(good for attack)than PA60/80 where keys have (1/4 to 1/3) dead area before it starts to respond velocity.

Piano is not bad at all.very playable in live or recording.the area (A1 to C3) can be a little bit nasal but the lower and higher parts sounds good.overall PA50 does sound like a good sampler with great samples (and well balanced responce)and PSR 1500 sounds like a pumped up home keyboard (with only few good sounds)which is a fact.

almost other sounds in PA is sweet,live,cool voices in yam 's terms.yes PSR simply can't beat overall sound quality of PA.

but on the other hand newer technology and ease of use make PSR 1500(and 3k)shine.
interaction between arranger and mid file playback,SM card and USB to device,and great screen(where in PA most of the screen is wasted with dumb and confusing design),4 realistic fills(instead of 2 mostly erratic fills of PA), multi pads which can do what they are suppose to do,and ofcourse mega 3 rd party style support of yam.

so I'm repeating these. http://www.synthzone.com/ubbs/Forum37/HTML/009086.html http://www.synthzone.com/ubbs/Forum37/HTML/009096.html http://www.synthzone.com/ubbs/Forum37/HTML/009195.html


piano wise they both are not great.1500 is like outdated(was good in early 90's) old home KB piano which is playable.PA 50 is like some "not that great" patch(but usable) in a new pro sampler.so they are in the same level.good points for PA here is you have more usuable ac piano patches(L/R piano/piano and strings, etc).
mind you- other sounds(including vintage EPs in PA 50 will blow 1500,3k and tyros out of water).

but styles and versatility wise psr is also way ahead than PA.