If anyone thinks the Turbo could replicate, say, Gunstar Heroes without any loss whatsoever then they are fooling themselves. That being said, anyone who thinks the Genesis could replicate , say, Air Zonk exactly would also be a fool.
The MD couldn't handle Sapphire, but the Sega CD could (with the requisite color loss, of course). I'd like to see the Arcade Card handle Batman Returns or Soul Star. Or Super Castlevania IV. Can't be done, not even close. But really, who cares?