Jeez, I really don't like either that much. Mario 3 is still my favorite. But if I were to choose, I'd choose world. It's just the more fun game, with more replay value. Don't get me wrong, 64 did amazing things for gaming, but it wasn't too long before it was overshadowed technically. Mario World stands the test of time I feel, better than 64.

Super Mario World for sure.

I love Mario 64 and its probably equally as groundbreaking in gaming BUT I think Super Mario World is one of the best replayable games of all time. Its got a ton of original levels and areas and just absolutely killed (in a good way) the idea of a platforming game with an interesting explorable overworld in terms of branching paths to go through levels

Obviously games before it like Mario Bros 3 had the overworld but Super Mario World perfected it. I mean look at something like Super Mario Maker and it indicates the signifiance of the game 

at any rate I like both but as cool as the castle and everything is in Mario 64, I don't find it anywhere near as immersive or varied. Mario World I definitely have killed way more time with and I feel like playability wise its as enjoyable today as it was in, what, 91?

what would you consider better in Mario 3 compared with Super Mario World? I feel as if they are good comparisons because they have a similar structure with the overworlds, but Super Mario World has a lot larger varied amount of levels and enemies, AND actually has an overworld that lets you decide what order you do SOME things in

That's the thing, I like simplicity in my Mario games. While world is the more robust game, it's just my personal preference of simplicity coupled with fun. You could argue that Super Mario World is simple, but it's much more complex than 3.  It definitely isn't nostalgia because the first Mario game I played was um...I think it was either World or Sunshine. I can't remember. But I guess in a sense, World is objectively the better game.

I found Super Mario 64 was a step down from the classic 2D Mario games in terms of game play and level design.

I love both but... Super Mario 64 for me because it's 3D.

Definitely Mario 64. Probably the game that I have the most fun playing.

Super Mario 64. Now while I also like Super Mario World, I find it to be a little on the easy side and while the level design was good, it was overall a step down from Super Mario Bros. 3 which is now my go-to Mario 2D platformer. For me, Super Mario 64 is the best of the 3D Marios with it's intricate design and mechanics so I still like to go back and play it time and again.

SMW, it still holds up to this day. Mario 64 is really starting to show its age, and there are superior 3D platformers on the N64 like BK1+2 and DK64.