This is an older tread, but it's a good question, and for the sake of internet searchers I thought I'd add my experiences.....
I'm on my 4th rear tire, second front. I'm a big guy, and I carry a lot of stuff, so the scoot's about 60 lbs shy of max payload. I remove my own wheels but leave tire mounting and balancing to the experts.
The rear Maxxis that the bike came with lasted 5k miles, the second one lasted 4k. Decent tires, pretty grippy and not bad in the rain; they feel very stable, no doubt due to the tire's flattened profile. But only available through my dealer around here, who up-charges OEM parts and wants outrageous bucks for mount and balance; definitely too expensive considering I was replacing them so often.
I next went to a large local MC shop - I wanted a Michelin but they were backordered at that time; I didn't want a Kenda so I went with the Avon. It was about the same price I'd paid for the Maxxis but a lot less for mount and balance. Unfortunately I got a defective tire, it wasn't properly round and the bike bobbed up and down at certain speeds. The Avon was also the worst tire I've ever experienced in the rain, to the point of being out-and-out dangerous. I dumped the scoot at ~10 mph in wet weather because it didn't grip when I hit the brake. Just turning a corner in the wet was an adventure; that "wiggle" as the tire decided whether it was going to grip or not was heart-stopping. Needless to say I returned the tire within a week, one ride by the technician was all it took to get my money back.
At that point I was realizing that living another day was more important than the cost or the delay, so I put the scoot away for a few weeks and waited for a set of Michelin Gold Commanders. They were more expensive, by about $20/tire, but they're grippy both wet and dry, smooth and quiet. The Michelin's profile is much more rounded than the Maxxis, so the scoot feels a bit more "lively" and less sedate, but you get used to that quickly. They've been on my Xciting for 7500 miles now; the front is wearing very well and will give me another 5k miles at least; the rear is ~0.5 mm away from the wear bars and will give me maybe another 1 or 2K.
What will I buy next? Another Michelin without a doubt. Unfortunately, the Gold Commander is now discontinued, but there's a few still available here and there; if not then the Michelin City Grip.
Colin.