hey sarah, welcome!
i am sure you'll get enough answers to your question, and also if you search among the previous posts, you'll be able to take a good decision.
if you got the chance to try both of these instruments, that's already very good. your ears are the best judge when come about sounds and styles.
as a previous pa50 owner, i can tell you i was quite happy with my keyboard, the sounds are good and styles are modern. still, i didnt like the os, i thought was too many pages in the menus, etc.
features wise, probably is more customizable than psr.
pa50 is more like a workstation. more to learn. longer to get all the benefits.
psr seems to be quite easy to get around with, easier os, also good sounds too.

my opinion and advice to you: if your looking for easy more user-friendly os, go with yamaha. still keep in mind that pa50 does the work excellent and gives more modern feeling to the styles.

both are flexible enough to help you do whatever on'off instruments and so on...