I bought used steel over the wheel tracks for my bobcat 763.
Steel tracks completely change the machine. You will lose maneuverability, but the traction and flotation gain are amazing.
I was using my machine to enlarge an existing pond. With tires I would sometimes hit wet pockets and either bottom and or/spin wheels in the "hidden" mud. After I bought tracks, there was just about no where I could get stuck. In some spots, the ground pressure was reduced so much I literally floated across some wet pockets.
I'm a huge believer in tracks when conditions warrant. But you cannot drive the machine like your accustomed to on wheels.
Comments about solid tires are valid, especially if driving in areas where you can get sticks jambed between tires and tracks. Also make sure tracks are relatively tight over wheels-too loose and you can end up cutting into the sidewall of a brand new tire(expensive lesson)...
I'd say I use my tracks about 10% of the time, but that 10% is like having an entirely different piece of equipment for the price of the tracks.
The tracks come up for sale fairly often as most people don't like hanging on to them for that 10% of the time. A good set of steel tracks is very heavy, 400lbs each or so. I keep my rolled up on a pallet.