Star Wars Republic Commando combines all the basic elements of a good FPS into a good sqaud based shooter without flaws.
RC combines nice graphics and visuals with good sound effects and music to make an experience that kind of pulls you in the Star Wars universe. Add that on top of the great AI your squad has and you have a nice game. The AI is one of the best if not the best of sqaud based games. You never have your sqaud running in the opposite direction or getting stuck behind a box and never going around it, they always follow orders and there never seems to be a problem with them completing them.
The length of the game is just about right... its not too short to leave you feeling ripped off or too long to leave you irritated. There are a variety of enemies and different enemies have different difficulty levels, none of them are a problem if you use the environment and position your squad accordingly; for example putting your squad in sniping, anti-armor or grenadier positions will dispatch enemies quite easily and nicely. One of the annoying points of the game are the SBD droid dispensers. It can sometimes be hard to find breaks in between the SBDs being released to get in there and set a detonation device without getting spotted and incapacitated, most of the time though, the dispensers are arranged in a way that you can distract the attention of the SBDs with your other squad members and set the detonation device and blow it up. Other than that there aren't many irritating spots. Varying levels of difficulty and varying enemies help to make this game as fun as it is.
So all in all Star Wars RC is a game most all Star Wars fans should enjoy, as well as most FPS fans. It combines all the elements listed above nicely into a great gaming experience. Add that on top of good voice acting and you have a good gaming experience.