Despite the fact that it's quite short, I thought I'd still point you over to this retrospective for Star Wars: Knights of the Old Republic on Gamer Bliss since we're quickly approaching the ten-year anniversary of the release of BioWare's excellent sci-fi RPG. Has it really been that long?
As far as gameplay goes, the battle system is extremely user-friendly and easy to navigate. The d20 model is appropriate given the different types of weapons and magic used by the various character classes and their unique modifiers. The upgrade interface is quite straightforward, and the lightsaber crystal structure provides a nice degree of customization.
In addition, players have the opportunity to choose the Light side or the Dark side of the Force in various situations. Whether it's choosing to keep someone alive, helping local thugs or picking unnecessary fights, what you do (or even say) can affect your alignment. You can choose to remain neutral, but your character must be categorized as either Light or Dark to use certain weapons, wear certain armor and gain certain abilities. This aspect of the game gives it strong replayability. I know I'm going to make an (evil) character the next time around.