Great topic ...I have a 4x4 Kawasaki 650 BruteForce ATV and it gets me to most of my backwoods lakes almost all year long, except for when we get a winter with lots of snow!! ......the quad is powerful, but the ITP Mudlite tires just dig down in deep snow to a point where the bike gets hung up on the undercarriage and then that's it...you're done!!
I also have an older sled that my wife uses now but even then, I've had nightmare trips burying it in deep snow while trying to break trail gettin' into some of the trout lakes. and then having to pull it out ..
This is my next purchase for the ATV and then there's no stopping me as far as where I can get to year round!!!...
The track kit is a little steep ($3800), but I figure it would cost me around the same $$$$ to buy a used sled.....on top of that I'd have to pay insurance for the sled and then spend the $$$ on yearly maintenance....