If you liked Super Mario Bros., get it. If you've never played Super Mario Bros, get it. If you don't like Super Mario Bros., don't get it.
Basically, it's the original 1985 Super Mario Bros. and the real (Japanese) Super Mario Bros. 2. It also includes a challenge mode where you must earn medals on each stage for finding red coins, eggs, and lots of points. There's also a 2-player race mode. It's a very good update to the original and strongly recommended by me.
"Thus Spake Lizard"