I picked TFU. KOTOR was fun the first time I played it (sort of), but after that...well, the story had no surprises the first time through, much less the second time through, and turn-based combat is simply something I don't enjoy. Getting through the game after the first playthrough seemed roughly equivalent to pounding my head on my desk. Still, I pushed through all four alignment/gender combinations--when I was done, I wanted to throw the game out the window. Since then, I've gotten it out a couple more times and played through Dark Side/female a few more times. That desk didn't get any softer.
TFU, on the other hand, has replayability (at least, for me it does.) I got the game shortly after it came out, and I've played it a lot since then. Frankly, I've had a lot more fun with TFU than I've had with KOTOR.
Chapter 12 of A Soul Adrift
: On the planet Felucia, a young apprentice of the Dark Side thinks back to the beginning of her training as she lies in wait for her prey...
All the Time
: After four years in the Unknown Regions, the Exile returns to the known galaxy to visit an old enemy.
: A master of the Dark Side finds himself about to lose the one thing he cares about--and he will do anything to stop her from endangering herself.