I've had bad experiences with the sensors in the previous mad catz, but these seem to be using modern more common sensors.

The RAT Pro S is using a Pixart PMW 3330 optical sensor. I've tried searching the forums but I couldn't find anything on that particular sensor. Is it any good?

The RAT 4 uses a Pixart PMW 3310. An older sensor, and the RAT 8 uses a Pixart PMW 3360 (what my Zowie uses I believe).

Strange that they would go for a variety of optical sensors, maybe because they get the old ones for cheaper?

I want a Mad Catz because of their ergonomics. Due to my three finger grip (my middle finger uses the mouse wheel, wedding on right click), I can't use the mouse buttons on the side of the mouse. For example on my Zowie ZA13/FK2 I can't press the mouse button five comfortably. If I press it, I have to weaken my grip on the mouse and that effects my aim.

So I need something that's optical and adjustable.