Do NOT buy this - Notoriously buggy, and a bug that after sometime you can't select your units
After messaging LucasArts about it, they don't seem to ever be fixing it, and therefore I can only advise that this game is broken except if you only want to complete the campaign.
If you do still decide to buy the game, you should check the LucasArts forums, Petroglyph forums, and other fansites like everythingeaw for threads on things like 'unable to select units' before you do so, as I believe any Star Wars fan will be frustrated with this game in the end. Even Petroglyph confirmed with me that the game engine needs patching, but they can't do anything without LucasArts giving the go ahead.
If this bug didn't exist, the game would be otherwise almost perfect.