I found a PS2 version Nuby SF2 controller for $5 today. I don't own a PS2 but I do have a USB adaptor for PC, and figured it'd be good for emulating Sega systems. The buttons are responsive, the d-pad is excellent.
So I have to wonder... why is the Xbox verison of this same controlelr so broken? I bought one off Amazon for $14 shipped. Buttons are only okay, the d-pad is awful, a bit under-sentitive and seems to have a minor delay.
Basically, while I found Megaman ROMs very playable on PC with the PS2 controller, using the Xbox pad with MM Anniversary Collection was an awful chore.
They seem to have the same d-pad but while my PS2 controller has a smooth d-pad, the Xbox version creaks like mad. In fact, they almost seem to be the same controller- same size, almost identical cases and buttons. I have to wonder if there was a factory switch, or if they simply couldn't optimize this thing to work with Xbox hardware. The PS2 version has the PS logo on it and is licensed by Sony, but the Xbox version seems to lack any sort of MS branding.