There's a guy on BurgmanUSA.com who bought one a year or so ago. This is a stand-up guy, long-time member there (former long-time owner of a 650 Burgman, maybe two of 'em), who knows what he's doing, 60-something years old, rides in winter in Ohio, etc. And we both hosted one of the admins from that forum, when he was traveling from the east coast back to the west coast.
He does his own maintenance, just constructed a trailer hitch setup for hauling a Unigo with the 550, yada yada. He has nothing but praise for the bike, including power and handling, ease of maintenance, quality of construction, and so on and so forth. And he's shared a tremendous amount of his new-found knowledge there, particularly with regard to maintenance tips, for prospective 550 owners; I'm talking oil changes, what aftermarket brake pads are equivalent, and so forth.
The 550 is significantly lighter than the now-defunct Big Burgers, and so power-to-weight is essentially a wash, I believe. And the 550 is way ahead, in terms of electronics, for instance, than anything that appeared on the Suzuki. Oh, and despite the reservations of the OP here, belt final drive on the AK 550 (which, recall, is my favorite final drive). And now cruise control, too. My local dealer of little-baby-Kymcos offered to get a 550 for me ... if I first paid for it.
I tell you, had Kymco USA been a little more responsive to my requests -- such as what dealers, anyfreakinwhere in the USA, might have one on a showroom floor -- or if Kymco had a recent presence at Americade (they did, some years back, at least once) I might've become an owner. (My queries to individual dealerships in the northeast didn't result in locating any, either.) I wanted a replacement for my then-15-year old Big Burger, fearing its days were numbered.
And then we did those tours in Europe on the C 400 X, my wife liked it, and game over.