I used my Battle Pad for the first time the other day.
IMHO, this is by far the worst controller ever made for the PCE/Turbo platform. At least, the worst one I have ever used.
The only thing going for it is it's shape, which actually makes it pretty comfortable to hold. So what's wrong with it, then? For starters, the turbo switches are mounted along the top edge of the controller. They are in the center, out of reach of BOTH hands without completely letting go of one side. This makes toggling them in mid-action impossible. But the real killer here is the D-pad. The D-pad is a crosshair shape, unlike the circular design 90% of all other Turbo controllers use. And it's STIFF. These two factors make diagonal moves in shooters impossible.
So what good is it? About the only time this controller would ever be of use is in a slow platformer where diagonal movement doesn't exist and toggling turbo speeds isn't vital. It's too bad, too, since the ergonomic design is kind of cool and very comfortable to hold.