Yes they are older , but not outdated . They are all sample playback machines , even the PRS you looked at . Since they are sample playback , and EVERY company is just reusing their sample libraries over and over in new models , you do not have to buy a new model . You have to take the time to check into them . They can be found at Harmony Central , Ebay , used music stores . The JV , XP , XV models from Roland are the same , the only differences are small features like effects , arpeggiators , and the number of sounds .
The same sample libraries from the Korg N series I.E. N364 is in the later Trinity and Triton models .
The S series from Yamaha has the same samples as the earlier W series .
If you must have new models , The Roland JUNO-D which is a professional board is less than $600 and will hold value much higher than the Yamaha PSR .
The Yamaha S-03 is another .
The Korg Triton LE is not much more than the Yamaha .
Other used boards are The Korg Karma , Yamaha W-5 , Roland xp-50 .

I am analog guy myself . I've been using analog synthesizers for 22 years , these are keyboards made from the 60s , 70s , and 80s . These boards you don't just push a button and play a sample . You must build the sound from the ground up . Their is alot available to you .
http://www.harmonycentral.com http://www.vintagesynth.org http://www.sonicstate.com http://www.synthfool.com http://www.moogmusic.com http://www.galaxymusicusa.com
Check them out .