My girlfriend and I just played through SM3DW together, and it's some of the most fun I've had playing a video game in a good long while. Without thinking about it too much, it's a solid (surprise?) contender for the best Mario game I've ever played. It has all of the familiarity of digital cardinal direction Mario gameplay, but with an inventiveness, attention to graphics and sound, and overall freshness to it that the New SMB series has just been lacking after so many similar releases.
I was worried going in that with EAD Tokyo's games going in a more and more linear, simplified direction (Galaxy --> Galaxy 2 --> 3D Land --> 3D World picking up gameplay influence over time from the success of the NSMB series) that there wouldn't be the sense of wonder and open exploration that you got in 64, Sunshine, and the Galaxy games, but the exploration is all there, you're just doing it with friends, under a time limit, which just encourages you to replay the levels more (with getting green stars feeling most of the way like exploring for secret stars/shines).
I've been playing a lot of Mario 64 lately as well, and while I've definitely been pining for another single-player-oriented, more exploration-heavy 3-D Mario game, we had SO MUCH FUN with Mario 3D World that I think I'll really miss it with Odyssey-forward if EAD abandons the SM3DW multiplayer D-pad 3-D approach and leaves 3D World as just lightning in a bottle on the Wii U.
(3D Land was great, but going back, it does lose something in comparison without 60 FPS gameplay and the D-pad option)