I've used the 27.5 ones for 3 winters so far. No sealant to top up and no mess to deal with when swapping tires. The difference in the way the bike rides was noticeable on the first ride. The valves are plastic, so you do have to be careful, but I've had no issues. I'll be buying them again if I ever have any issues. A couple of my buddies are also using them with similar experiences to mine.
I ride mostly trail on a Fatboy in the West, so lots of thorns. I really didnt want to mess with sealant and air leaks so the idea of lightening up and the convenience of changing out tires with little hassle, really appeals to me.
I've looked around and cannot find a dealer in the US for the .Fat models. Where have you found them?
No thorns whatsoever where I am. Do you get any flats with regular tubes? We tend to run very low pressures in soft snow (3 to 5 psi). The revoloops are popular here since a tire burp in freezing temperatures could have severe consequences.
One of the lbs in my area carries them! Hopefully they'll ship to the US if you decide to go that route.