I would not hesitate to buy a used one again, but I didn't buy one that was clapped out from years of tire store use.
I think I paid $500 for my used Atlas a few years ago. It was in good shape, but unknown to me it had some corrosion from wet air inside the bead breaker cylinder which caused the breaker arm to stop working shortly after I got it. Had to take it apart and clean out the rust/corrosion and reset the seals in the cylinder- didn't even need new parts, but if it did, the guys at Greg Smith had them in stock. (They also were helpful in telling me what was likely wrong with it when I described the problem)
You can buy the new model like mine for about $1200. Ones with a few more features go for $1750. I'm not sure why anyone would want to pay more than that for one in a home shop. Mine doesn't have the black helper arms on the right and left shown in T_Raven's picture above. I don't think those are necessary, I've figured out how to change everything from motorcycle tires, to 10 ply truck tires on it without too much trouble. It does plain old 16 inch car tires with no sweat, and it's so much more convenient than taking them to a tire place or trying to do them with tire irons. The only feature I've found lacking is the bead blaster. I've had a couple of tire/rim combinations where it was nearly impossible to get the tire to fill. I bought a cheetah to solve that problem.
I don't know if an atlas would stand up to commercial use, but for a home garage, they work fine. Actually it probably would stand up to light commercial use fine, they aren't complicated machines. I've changed probably a couple hundred tires on it since I've had it. For those that are thinking about it, I would say it comes down to how often you would use it and whether you have the space. If you have more than a couple cars, or some teenagers who are driving, or a hobby that requires tire changes, it's not a hard decision to make, the machines can pay for themselves pretty quickly.
Keep in mind though that changing tires is hard and dirty work - mounted tires can be heavy, they come off the car with all kinds of brake dust and dirt on them, and you have to clean the rims to mount new wheel weights on them.
P.S. Just me, but I would not recommend one of those old style coats center clamp machines , even though you can find them cheap these days. I worked in high school changing tires on one of them and I thought they were great machines back then, and when I was looking I probably would have bought one if I had found it cheap. I can say with experience, the newer style rim clamp machines are much more versatile and easier to use.
