SMB3. It was more innovative, harder and interesting than SMW. SMW, while fun, was so easy, it felt like a game made solely for children. And I don't want to hear about the whole 100% thing... that's a cop out. SMB3's base levels in the 8th world (particularly some of those last ship levels) are harder than the hardest hidden worlds in SMW.
And did I mention that SMB3 is much more innovative? Yeah, there's that.







