I bought the USB version of one of these about a week ago and the start/mode button placement are my biggest complaints. Why they decided to implement them the way they did is a real head scratcher.
I agree with you about the mode button, it's placed where the right index finger sits and is easily accidentally triggered during play. That's okay with older games but some of the newer ones actually put some options on there which can make things difficult.
The start button sits on the same position where the old one on the og 3-button pads used to be, it's just flat because otherwise it would be in the way when using the X and Y buttons.
However, it being flat brings in new problems. I didn't have a 6-button pad for a while when I bought SF2 back in the day so I played it with the standard pad where pressing start switches between punches and kicks. After about two months of practice I became quite good at it and could hold my own even against 6-button users. Of course I bought a 6-button pad shortly afterwards and never really looked back but I was kinda hoping to recreate the old style with the BIG6 for nostalgia's sake. It's almost impossible, tho, because even if you hit the right spot, chances are that the flat button doesn't register it.
Can't comment on using the pads on any other machine than Genny, bought the 9-pin standard joystick version.
