I would say that U is the best installment in the NSMB series. I would also definitely say its better than SMB. I am not done with it so I can't compare to SMW yet, but that game will be tough to top...
Mario 64 is just too different for me to compare. So I won't
Monument Games, Inc. Like us on Facebook!
http://www.facebook.com/MonumentGames
Nintendo Netword ID: kanageddaamen
Monument Games, Inc President and Lead Designer
Featured Game: Shiftyx (Android) https://market.android.com/details?id=com.MonumentGames.Shiftyx
Free ad supported version:
https://market.android.com/details?id=com.MonumentGames.ShiftyxFree