I've been using an EdLaddin Seagull 78 for the past few years and love it. I much prefer a Sega Genesis pad over the squared-off corners on an NES-style pad. But nearly anything beats the PainLine!
Still prefer a real joystick for the 7800. Most of the games don't feel right to me w/ a dpad, but at least you won't get carpal tunnel from the PainLines!