Be wary of clone consoles, they're notorious for not being compatible with every game, and even with ones they are there can be visual/audio issues. Original hardware is usually best if you can go for that, but if you want a clone make sure you read up on it before buying.
I'm very happy with the modded Mega Drive I got back from
http://www.consolepassion.co.uk, so once I have some money saved up I'll be sending off a SNES for the same treatment
They even do a mod that allows you to play notoriously tricky games like Super Mario RPG and Kirby's Dreamland 3, though be prepared to fork £45 for it. Personally though I think that's worth it in the long run.