This has on-the-fly as well, but the presets are 500/1000/2000 dpi.
I bought this last time it was $13 or so after rebate. Certainly worth the money. First of all, update the firmware. There are like 10 different versions of firmware that all change the tracking and lift-off distance to different levels. I forget which one I have but you can probably look up online which ones are best. Next thing that I'll say is that this mouse is a little light for my tastes. It's certainly very well-made and not cheap feeling, but because of the weight it feels like the movement is a little loose, even at low DPI. I thought my MX518 was better for tracking in FPS's, even though this one is supposed to have a "perfect sensor." That said, it could just be because I'm playing CS:GO, which has some reg problems anyway.
At any rate, this is a pretty solid mouse, and a great back-up mouse if you're in the market. It's also good if you're a fan of optical over laser, like I am.
excellent points. I am using this mouse now, and I had updated the firmware. Also: note that there are no drivers from the company.