(Long, first post of most probably nothing that hasn't been said. I really, really apologize.)
I just finished the game a few hours ago and feel like adding my two cents. As for my vote, I liked both games. They both had their strong points and flaws but as a whole, playing both games was time well-spent for me. (Even if, in retrospect, KOTOR 2, admittedly, isn't as solid as I wish it would be.)
I was prepared to write something pretty long (Um. Longer than this anyway.), explaining why I think such but I think there's more or less an agreement (though grudgingly for some) that KOTOR2 is a good game on its own (so I don't really have to elaborate). It has its bugs and glitches, its plot holes and questions but I think it does have a fighting chance against other RPGs in the market. Enjoying the game is a pretty relative thing anyway. I don't think the game is so bad that you want to chuck it out of the window. (It isn't bad at all.)
I disagree about the story being mediocre though. (Well, technically, I guess it can be described as mediocre because of the painfully obvious plot holes) But still, I found the plot to be more intense and profound than the first. The plot wasn't simply a 'saving the galaxy' sort of plot. It involved the characters in a deeper level. I found the characters equally engaging and I liked the fact that it was a darker story and things weren't as simple (though simple is good). Also, not being sure who to trust kept me on my feet and paying attention throughout the game. I don't know. If KOTOR and TSL were books, TSL would be more up my alley, I guess. (Without the plot holes.)
I found myself caring a lot about the plot in TSL. I really wanted to see what would happen. (As embarrassing as this is, I remember my main motivation during KOTOR was to advance the romance quest. Shh.) I really got more caught up in the plot.
Or it could be just because I played TSL more recently, thus remember it more clearly and be a little bit more sentimental.
I can't really refute the criticisms because a lot of them are true. There are so many aspects of this game that could have been improved. They already have a great plot in their hands. Note that these are criticisms though. Having a lot of them doesn't mean you suck. A lot of things were and are going against Obsidian. First of all was that deadline and second, they had a lot to live up to. TSL can't really avoid being compared to its predecessor and since its predecessor is a 'first' of many, you can't exactly expect them to beat the prestige of that.
I hope Obsidian does take note of these criticisms. Especially if they are going to make a third installment. (I hope they are.)
To sum up, I love it as much as I love KOTOR. (I guess we can attribute a little bit of nostalgia to that). Don't let the complaints discourage or influence you. It really depends on what you look for in a game. For me, it IS a good game. It DOES live up to its predecessor. Why would I play the sequel anyway? Because I really like/d the KOTOR universe and I really like/d the way their writers think and write. Honestly, I think I'd like anything KOTOR-related (and like them equally).