Well the one thing the NES version did better was the box art. Damn SMS box are sucks
Yeah, there's really no comparison there. I never have understood why Sega chose to skimp in the box art department. I also thought it was lame that they usually gave the main character in the picture childlike features. I figure that was the age bracket they were targeting but I think it would've been much wiser to go the more artistic and mature route as is shown in the NES artwork.
As for the game, I only have the SMS version. It's a fairly good shooter but it's a bit more difficult than I think it needed to be.