I've always been a big fan of Bejeweled style games. Diamond Twister is that and more. It features a nice story line and many modes that you can unlock throughout the game. I have yet to run into a crash or a bug. All seems very stable. The graphics are great, and the music fits very well with the game.
The only thing I could complain about, is that the jewels are a tad small. Someone with large fingers may find it hard to move them.
For $4.99 ($5 cheaper than Bejeweled 2), it's definitely worth the purchase!
For a video review, see:
YouTube - App Review: Diamond Twister
Have fun!