I felt like a trip of nostalgia and picked up all three games. This really is a great set of games :) I can't remember the last time I waited so eagerly for the final chapter in a game series.
The first I loved for its overall feel and animation. The prince didn't have a lot of fighting abilities, but being able to leap over someone and shank them with a dagger, then proceed to cartwheel over and do likewise to a fallen victim looked fantastic.
The second was darker, and had a more mature, morbid feel to it that was great for me, but felt a little out of place. The combat got beefed up with duel wielding, throws and a good amount of freedom. Plus, the new gore and decapitations made the blade and boot breakdancing really cool in slow motion.
The third I felt struck a perfect balance with what the first two tried at. It managed to stay true to the artistry and general feeling of POP1 with the settings and music, but also managed the dark, morbid feel of POP2 without having to throw in out of place metal music.
The story was great, the graphics great, the games fairly long for an Action/Adventure title, and the story was just fantastic. The endings were always satisfying, and the first time I played through all three and defeated the end level boss of POP3, it really felt like a trilogies ending should. Fulfilling and worth while.
If you really haven't played them yet, in which case, take this final line with a boot to the head, I suggest you go and pick them up. They're in the budget line and fairly easy to find these days.