Buying
Having just bought a BH, I cannot over emphasize having it checked out by a mechanic before you buy. Parts are expensive: probably because the dealers operate from the perspective you are a commercial operator. I have spent a lot of $$$$ on my unit to get it up to good operating condition.
The problem for me is the trade-off between doing repairs yourself or having a mechanic do it. For example, when putting on new seals on a swing cylinder, the bolt holding the seals needs 950 lb/ft of torque. Do you buy the equipment or have it done and pay?
Wrenches on my Case 580b require 7/8" and greater for any larger part that needs to be worked on to get to the repair. You can buy wrenches, or a large compressor for impact hammers if you are going to have an on-going need. In my case, I bought the BH to clear my land, and once I am done, I intend to sell it. It is a tough trade-off between buying the tools you need and paying a mechanic since getting good money on "used" compressors, impact tools and wrenches is difficult. Not too many people need 2" wrenches. Your call, just some of my experience.
One more thing. Though I needed a BH for my situation, take a look at the more powerful skid steers. They are more compact and may be suitable depending on the work you need done.