I also had the swamp lite 26'' x 12 on my RZR for about 4000 km and here is my impression of them.
They are great tires in cool/warm weather, in mud and hard pack trails but not so good in cold/very cold weather, heavy snow and are a bit noisy and bumpy on asphalt. I found that the big and spread out knoby treads do not have the ''paddle'' effect that pushes the somewhat loose snow behind you so you spin alot. They are also very stiff tire (bias 6 ply rated) and because my RZR with walker evans shocks is very stiff to begin with, i had quite a bit of a hard ride but i guess because of that i only had to repair one small slow leaks over the 4000 km i owned them while my friend had many many times flats tires. I also find the tires to wear a bit fast so as soon as the rubber worn down enough to get rid of all the little holes in the spikes (around 2000km), i had studs put in them and that stopped the wear a that point. One more thing i noticed is because the spikes are so high, they are prone to actually cut off and almost tear off if the tires happens to spin on hard rock while the tread is frozen and last thing, only when it is very cold and the rzr sits outside for lets say the whole night and because the tires only have 10 psi in them, when you start rolling, you have that bumpy out of round ride for a very long time before it evens out.
Like i said, very good and very though tire in warm weather but best to have a different set in a cold one.