I got Mario 3D Land on release day, and Shinobi yesterday. I must say that Shinobi held my attention for much longer with its "one more try, I know I can do it this time" gameplay. Kinda like Dark Souls, except more about twitch skill than understanding behavior.
I loved Mario nonetheless. Gonna try to blast through to the end stages that I hear so much good about. (we used to do extreme speed runs through bowsers final stage in Super Mario 64, so I'm looking forward to some X-TREME trick style levels in 3D Land)