I read mostly positive posts about the TO-30, along with one guy that was complaining about having to do things to his that are common to do to any model. I picked mine up at a flea market store for $1,700. I paid that much because it had almost new tires, and because I could tell that all it needed was a valve job. I trailered it home, yanked the head off, and sure enough found 2 burned exhaust valves.
I ordered 2 new valves, a head gasket, 4 brake shoes, a muffler, points, plugs, and plug wires, a inline fuel filter, and a spin on oil filter kit. All the parts came to about 225 dollars.
I spent a few hours after work for a week, then the weekend getting everything done. I was right that all the engine needed was a valve job (I lapped the valves myself in my garage). It has really great compression now, and burns no oil.
I bought it to clear a 1 acre lot that I bought. The lot was in the natural state, and was covered with weeds and mesquite. I filled in rain cut ditches that were 150' long and 3-4 feet deep. I now have the lot leveled flat as a pancake (with the blade that I bought for $200), and I just put a "will build to suit tenant" on it. I couldn't be happier, and have been completely amazed at what serious work horses they are.
If you have any property or land at all, get one of these. They'll do far, far more hard work than you would guess just by looking at their small size. They're nothing but amazing. Happy hunting if you don't already have one.