I really liked this game, and as someone said, I think its one of the best released sofar.
The environments are cool (

) and there isn't that many games that have snow as its theme. I also like being outdoor and not crawling inside tunnels all the time (like most shooters does) and there is pretty much of outdoor in Lost Planet.
The story was ok, neither great neither bad. I agree the ending was abit bland, but up to that I enjoyed the story and especially the lengthy cut-scenes. I think more games should take inspiration from this and make longer cut-sequences as it makes the game more fun and the story abit more deep and interesting.
This is definately one of the games I will recommend to my friends.
Regarding the length of the game, I completed it in about 12-14 hours of total gameplay (over several sessions) and that is not that bad. Compare that to Gears Of War that I completed in like ~7h (on easy) or Open Season that took me 5-6 hours to unlock all the 1000 points! So yes, perhaps the game is abit short, but on the other hand there is many examples of games that is much shorter than this one.