I'm at the give-up-after-ten-minutes-and-throw-it-at-the-wall stage.
I gave the first model to my then 6 year old son. He had it done in less than 7 minutes.
I was not at all surprised that he was offered a full ride to MIT when he was only 16.
Me, I've never managed it at all.
Yes, and there are no "levels" once you know how to solve it the combination patterns make no difference whatsoever to the solution. I can do a cube in under 2 minutes usually, not sure if that's good or not, world record is 6 seconds or so??