Start with the job, not the machine. A 70 to 90 horsepower skid steer covers most contractor and farm work; go bigger only if you run heavy attachments all day.
Hours matter less than how they were spent. A 3,000-hour machine that moved snow in a parking lot is a different animal than one that ran a mulcher in the bush. Ask what it did.
Radial lift is for digging and loading flat; vertical lift is for loading trucks and placing pallets. Pick the one that matches your week.
Tires are cheaper to run; tracks float on soft ground and cost more to replace. In Manitoba and Saskatchewan spring, tracks pay for themselves.
Five questions for the dealer: Was it a rental fleet unit? Is there a service history? Has the hydraulic oil been sampled? What attachments are included? What is the warranty on a used unit?
Then ask for a quote through Find Equipment. The dealer calls you, and you can compare it against a second one in the same afternoon.