I've played the chess game a few times.
The boards and pieces look pretty good. I wish they were a bit larger, taking more advantage of the screen real estate.
The game has a library of famous chess games that you can select and play through. That's nice, even though it's a small number of games.
The interface is pretty good. The preferences options make sense, such as 2-D or 3-D board, strength levels range from easy to master, you can set a maximum think time per move, you can play vs. the cpu or human vs. human (if you don't have a real set and board handy). Entering moves is a bit clunky, as you might expect. You have to tap or click to get to the piece you want to move, press the center button, then tap or click to the square you want to move the piece to, then press the center button again. Fortunately you can move the cursor diagonally so that saves time and clicks.
The clock/timer display serves no practical purpose. I would expect it to actually time each players' moves. The program has no time control feature, so the timer is superfluous unless you need to keep track of how much time your spending on a game.
While playing your game you are treated to a serene classical music track. It does get a bit boring, but it's not intolerable.
Playing strength on the expert/master level is pretty good. The program knows some rudimentary book lines. It's style of play is rather unorthodox, but very effective. In other words it can beat a strong player. The downside is that it's kind of slow - it takes too long to move at the strongest levels.
Overall, if you've got time to kill and want to play a challenging chess game or two, this will keep you occupied. And it's conveniently running on your iPod - for only $4.99.