I just bought the program today, and played a few games. I'm a fairly good player, but I usually just play non-serious games. It seems to take about 1 second/move on level 7, and about 3 seconds/move on level 10 on my Kindle 2 USA model. It didn't make any howlingly bad moves, so if you're a beginner you should use the lower levels. There is also a mode to play another person instead of the program, and it has a 'how to play chess' and instructions.
Here are some things to consider:
1) If you leave a game in the middle and put your Kindle to sleep, it remembers and gives you the option to resume the game the next time you open it, which is a nice feature.
2) It doesn't seem to suck up very much battery on my K2, which I was worried about.
3) It has a good display at the bottom which shows the pieces taken by each side and the moves in standard notation.
4) You can 'take back' moves which is good if you're a beginner. (OK, I cheat sometimes too when I'm fooling around trying different tactics.)
1) It doesn't seem to have book openings, as other reviewers have said, which is slightly annoying.
2) It likes to exchange pieces, even when losing (which is not a good tactic, and typical of some chess programs).
3) When you advance your pawn to the 8th rank, it automatically gives you a Queen instead of giving you an option as per the rules of chess (there are certain times when you don't want a Queen, such as when it results in an instant Stalemate).
Still, in spite of some of these, I liked it. It has a nice, clean interface, runs quickly, and doesn't seem to make any big obvious blunders.
So, if you like to play chess, I think it's priced just right and worth getting for playing a game when you're bored and don't feel like reading.