For comments on POP: Sands of Time, have a look at
this thread or, for my personal opinion, I refer you to my sig
.
SoT is fantastic and worth every penny of the budget price you'll pay for it now. I've only played the demo of Warrior Within but will buy it when I find it for a suitably cheap-arse price. If you try to consider SoT and WW as two unrelated games, you'll probably enjoy the latter a lot more. If you go in expecting Warrior Within to be a sequel faithful to the Prince of Persia franchise, you're likely to be a little disappointed.