They all shared similar problems, with hardware that was far less powerful than the arcade, and cartridges that couldn't hold nearly enough data. They also had one other similar problem: inadequate controllers. None of these systems had six button controllers at launch, and it wasn't until Street Fighter was released for these systems that it became a serious limitation.
Several companies stepped up to fill the gap, but few so creatively as the Capcom Fighting Soldier pad. Designed by ASCII and sold by Capcom, it was almost certainly the strangest pad ever released.
Looking at it for the first time, it seems to be completely and impossibly unwieldy. The buttons are not on the same plane as the d-pad, being instead tilted forward on a separate platform. It looks absolutely bizarre, but it actually works.
The d-pad half of the pad seems to be a descendant of ASCII's GRiP controller, and could almost be considered a one-handled precursor of the modern, Playstation-like pads. Instead of a smooth handle however it has molded finger grooves that are comfortable even for my large hands. Like the Playstation pad, the d-pad is within perfect thumb range and the START and SELECT buttons, despite appearances, are easily pressed.
The button platform totally defies expectations. You might think by looking at it that they're in an awkward position, but they're not. They're at the perfect angle for players who prefer to use their fingers instead of their thumb, but - thanks to the curve of the platform itself, it's also supremely comfortable for thumbs as well.
From a quality perspective this pad is top-notch. It's well built, sturdy and it feels good in the hands. Even during a frantic session the pad does not creak or twist. The buttons have a nice response, the d-pad is perfectly punchy. You'd be hard pressed to find any pad its equal, at the time or even now.
The SuperNES version had a cross-shaped d-pad, both the 3DO and Genesis/MegaDrive versions had a round d-pad with a raised cross. Pretty much as you'd expect given Nintendo's d-pad patent. All three versions had a different colour scheme, to match the system. The MegaDrive version was orange and blue, 3DO was red and grey, and the SNES was grey and purple. The latter being a little strange in Japan, as the colours matched the US SNES but not the more colourful Super Famicom. The 3DO version had a little box near the console end of the cable, with an additional controller connector, allowing additional controllers to be chained together (a standard 3DO feature).
This image found on a Yahoo Japan auction
This pad gets my highest recommendation. There's no reason to prefer this over a normal SNES pad, but there's every reason to pick one up if you get the chance. It's better than nearly every other 3rd party pad available for all of these systems, and it's typically available at a very reasonable price.