How often do you expect to be renting equipment? The nice part is that it's always taken care of and if it breaks down, you don't have to repair it. But the cost of renting something over and over again will quickly equal what it costs to buy one. Having it sitting around and not using it is a very nice thing over the long term because it's always there when you need it and you don't have to think twice about using it. Taking out trees, picking up down limbs, digging a ditch, building up a road or just lifting something heavy.
The contractors that I know, and sometimes myself, rent equipment for jobs because it's faster and easier to have it delivered or pick it up for what needs to be done and the cost of that rental is part of the job. The client is paying for it.
As for tracks over skids, I don't care for either because I'm not a fan of skid steers. For everything they do, there is something else out there that does it better. Usually A LOT better!!!! The advantage the skid steer has is that it's small and easy to transport, it does most everything to a certain degree and it's very versatile. What I hate about them is they are painfully uncomfortable, everything they do takes longer then any other type of tractor and they tear up the ground worse then a dozer. Clients always complain about the damage they do to the ground, their lawns and especially their concrete. Nobody wants ruts and black rubber tracks all over the place.
Saying that, tracks have the ability to operate when tires wont. Skid steers with tires do not work well in mud. Even if the ground feels dry, if there is any moisture in the ground under the grass, a couple of passes over the same path and you will find the mud and get stuck. With tracks, you can operate right after it rains and pretty much keep going if it's muddy out. I'm not saying you can go through swamp mud, but wet ground and mud too slippery to walk on is doable. The mess is still there, but you are able to be productive instead of waiting for things to dry out.
Eddie