OMG! I'm so glad you asked! I LOVE THAT GAME! Hell, I loved it's predecessor "nibbles" on Dosshell!
So, my current phone's high score is 630. But I had 720 on my old phone (I got a new one when I upgraded my plan for some reason :s). I've never come close to the 720 though, since.
i play in the fastest level, i can't stand it slower, and i only use the 1 and 9 keys (using left and right thumb respectively), somehow i find it faster to play that way.