I have been working on equipment for15 years. One easy way to ensure a good skid loader is to put it on an incline with it running and see if it moves in with the controls in the neutral position. Movement would indicate accessibly worn motors. If the loader wants to move when controls are in a neutral position on a flat surface this indicates worn controls. worn controls can sometime be adjusted or by replacing worn ball joints in the linkage, but there are internal parts that wear that ,for the most part can only be repaired by replacing the component involved at a considerable repair cost. Very small movement in the internal mechanism is all it takes.
The best but not easiest is to buy one and years later look back . I bought a 1830 case years ago for a little or $3000.00 . It has been great the best thing i ever bought . I was worried that i wouldnt even like running it and it would have a major breakdown but its been great.
I worked at a case dealer. Case has a good product. Anything with hydrostat drive it is all about maintenance. Keep the oil clean and filters changed. They take a lot of abuse but dirt in the hydraulics isn't one of them. It is a death sentence once the dirt makes its way through the system.