adimatis. The PA50 is half the price in the UK as the PSR3000. I think the 3K is the better keyboard, just more polished in performance,but that's not de-crying that the PA50 is about the best board for the buck (better than PSR1500) but surprisingly the PA50 keybed is much better feel to play.
The reason I have added the PA50 is to marry up to the 3K on a dual stand. The combination should provide a good range of styles & sounds between them.