They need to be washed, fueled and ridden regularly or they get grumpy. More seriously, some find the seat a bit lacking (I don't), and a bit of a lack of room to stretch your legs (Kuryakin has a moderately inexpensive fix for that), and some buyers can't decide what option level to buy (there was only really one for me: the whole sheeboo). There is a degenerative disease of the wallet that usually kicks in post purchase that I call "farkelitis". Highly contageous and really difficult to get over (no 12 step program for that puppy).
If there is such a thing as a bulletproof motorcycle, it's likely the Wing. They are the two wheel embodiment of the Energizer Bunny, they just keep going and going...
BTW, welcome to the forum!