Well, all of the gamnes are great.
Warrior within may have a emo prince, but the story is also great, and the setting of islando of time is very well done, although it has that "one color" type of world like a quake game (brown or gray), but the level design is amazing. Sometimes it may cofuse you, since you go back and forth on the same levels in diferent periods of time.
Combat is an improvement, but now the upgrades are more difficult to find, and missing one of them may make it difficult, or even impossible, to get to the canon ending. So make sure you get all the upgrades.
The game is more difficult though, but combat is fun, and save points work almost like the first one. The look of the prince and his voice changed, but if you liked sands of time, WW is your best option for a different yet similar game to SOT.
WW is less "linear" than SOT and TTT, and is longer. The fact that you have to go more than once through the same levels may feel boring, but sometimes, finding your way, where to go is a puzzle in it's own way.
Then comes two thrones, which has the improved controls of the second game, but it is closer to the first one. The visual of the prince is closer to the second, but they brought back the same voice actor from the first, which is way better than the one from the second game.
The gamne has a feeling of the 1st game due to the similar enviroments and the linear progress. And it has a closure for the story the ties every events of of the trilogy, and has a very nice final dialogue, that makes you feel like playing the whole trilogy again, and again, and again...
People may say WW and TTT to be inferior to SOT, and they are, but that doesn't mean they're bad.
This game trilogy is one of the fewer modern games that I replayed more than once because it was addictive and had a great story. Some games nowadays are long, and even when they're good, once you finish, you're done with it.