The biggest difference about Rubik's cubing is that once you have mastered 3x3x3, 4x4x4, and 5x5x5 (which is just a slight variant on 3x3x3) all subsequent cubes are just natural extensions of these. A 17x17x17 requires no new skills that aren't already mastered in a 5x5x5, it just takes more time. The nice part of about this is you can really blow peoples minds by pulling out an 11x11x11 cube and solving it at though it were nothing.

Even sided cubes are the hardest because they have issues with "parity" that are only uncovered near the end of the solve and can be quite tedious to fix (at least imho).

Right, cubing scales up much more readily than juggling. Although I've found the bigger cubes aren't quite so impressive because you can't do them as fast. I take 10-15 minutes for the 5x5x5, and by then any observer has lost interest.

But yeah, some people will be impressed just because it's bigger. They always say that it must be super hard. My stock reply: "It's like a jigsaw puzzle. Is 1000 piece harder than 500? Not really harder, it's just more of the same thing." Sometimes that gets a blank look, sometimes that induces enlightenment.

My favorite cuboid variant is a 3x3x4. That blows people's minds when they see it's not symmetric, and they handle it and realize that it can't do certain turns (the long axes have to be 180° not 90°), but in fact that limitation makes it easier and I can solve it almost as fast as a 3x3x3.