I finally made it in and honestly a bit disappointed. There's a confluence of events that has led to that. It's been raining most of the day (not much they can do about that I know), and yesterday was a national holiday so it seems like it's busier than normal. I finally got in at 5, 2 hours before the park itself closes and several hours before parts of it close (eg Toad's café closes at 9:30) and yet both of the rides have closed before I even got into the Mario section.
The section is impressively made and full of life and character, but I've essentially spent a lot of money (and time) to walk around animatronics. The wrist band is impressive from a technical perspective, but as a wrist band it's crap. Bloody thing keeps falling off.
Ended up trying some of the challenges which are basically like Saturday night game show stuff (hit things, turns cranks etc) and it was a bit of fun but think the overall disappointed about the rides is dampening my mood. It didn't help that you can do 3 of these and then challenge Bowser Jr and after I'd done 2 they closed the rest. The coin blocks get a bit boring after one but they're more photo ops (and I'm by myself) than anything else.
The deserts part is in the main park so I did go there and it was good, although so much sugar I felt a bit sick as I don't have much sugar nowadays.
The only good surprise is the amount of Pikmin hidden things there are. Wonder if it's a sign of things to come.
As I was leaving they'd put a sign at the entrance saying it's closed for a private event tonight. Whole thing left a bitter taste in my mouth.
And to answer @bob (who posted while I was writing this), as in it was busy enough that 5:30 was the earliest I was able to get in.