I got both of them so I can tell you whats better.
New Super Mario Bros. 2:
A great game with.. More than 60 levels I think, Good grafics than the New Super Mario Bros. 1, + Coin rush (I think, Because I have special edition)! My Challenge is to get to 1 MILLION coins by coin rush and the solo play. There is Co - op play that I didn't tried but it seems to me very good. They added ( I don't know how to call it, sorry ) like the red portal there is gold one that adding more coins like if you are jumping without falling and touching the floor you will get 15 coins (5 + 10) and if you are doing it only on 1 monster or something else you are getting 5 coins ( 1 x 5 x 2 = 10 that means 5 + 10 = 15).
Power ups:
Fire Mario: Like the old games, you can get this power-up and you can shoot fire, pretty cool, huh?
Gold Mario: Like the fire Mario you can shoot gold that exploding when touching something not including the floor, and any monster that you are exploding bringing 5 gold, and if you are exploding 2 monsters at the same shot you can get 10, and then 15 and then 20 and then and then 25 and then 50, but: if you are exploding 3 monsters you will get 5 + 10 + 15 that means 30, and f you are useing the "portal" you will get x2 coins. You can also get the 1 up house or
Raccon Mario: you can kill with your tail and fly if you are running without any break.
Super Star: you can be ultimate and no one can beat you + the feature of 5 + 10 + 15..
Mushroom: Mario is getting big.
Big mushroom: Mario is getting VERY big for a limited time, he cant be beated and he can destroy anything he walk on.
Tiny mushroom: Mario is getting very small.
P - Wing: If you lose 10 lifes in a course you are getting the P - wing that makes you flying to the end of the course.
Invincibility Mario: The Invincibility Leaf (also called Invincible Super Leaf) is a
power-up that first appeared in
Super Mario 3D Land. This power-up is very similar to the
Super Leaf, but with added invincibility.
Super Mario 3D Land:
A great game with 16 worlds with 8 levels each world I think. The game is more difficult when you beating the 8 first worlds.
The game is WITHOUT the feature of 5 + 10 + 15 (x2) and without the gold "portal".
Power ups:
Fire Mario: Like the old games, you can get this power-up and you can shoot fire, pretty cool, huh?
Super Star: you can be ultimate and no one can beat you.
Mushroom: Mario is getting big.
Raccon Mario: you can kill with your tail and fly if you are running without any break.
Propellor: you can fly until a monster hits you. It can be founded in a ? block or a propellor (like ? block but its propellor)
Boomerang: you can soot a bomerang.
Invincibility Mario: The Invincibility Leaf (also called Invincible Super Leaf) is a
power-up that first appeared in
Super Mario 3D Land. This power-up is very similar to the
Super Leaf, but with added invincibility.
P - Wing: If you lose 10 lifes in a course you are getting the P - wing that makes you flying to the end of the course.
Statue Mario: In worlds 9 - 16 you can find a Statue Leaf that you can be a statue + the Raccon mario that you can fly and kill with your tail.
Hope it helps you!