You don't need to be a Star Wars anorak to enjoy this, but it helps. This was the first RPG I'd played in a good few years, and I was kicking myself for buying this when it first came out and *not play it* for nearly five years. (easily distracted by newer shiny things) Anyway, the Taris stage isn't as boring as you might think, and the only real downside is having to respond to the '*name* looks troubled, do you want to speak to them?' prompts which gets a bit irritating. Otherwise, it's as enjoyable as the rest of the game, though I agree, they could have included a few more unfamiliar areas.
Anyway, story: gripping; and variable depending on which companions you take at each planet (you get a lot of quests out of just changing characters). UI: easy, pausing games mid-combat gives a great way of reviewing how you or your companions are doing and the fact that it's turn based hardly matters because it's done so fluidly. Variability: brilliant, you can go to any of the four StarMap worlds at your leisure. I actually went to the Sith world quite early, and it was quite a feeling of achievement kicking their butts when I was still quite a low level Consular. Replayability: awesome! Light side/Dark side, take your pick, but choose Force powers carefully. For the sake of sheer fun, Dark side, naturally. Force storming, Force waving and death fielding mass enemies is so satisfying!