I never knew it had new levels, I just thought Vs. Super Mario Brothers was a two-screen, competitive version of Super Mario Brothers. I wonder why Nintendo doesn't want to re-release this version on anything... it seems like it would have been perfect to include in the 25 Anniversary package.
I wouldn't buy a reproduction for several reasons, including what MegaByte talked about, but at least this one doesn't destroy legit copies of games to make it. That's what bugged me the most about reproductions.