I've had Cycle Hill tire changer for about two years. It's made by No Mar, but a little more economical. I've changed about 100 bike and car tires with it and I am pleased with it's performance. It's paid for itself a couple times over. Like most machines, there's a learning curve with it, but it didn't take long to get the hang of it. It is strictly a manual machine and at times it does require some grunt to use. Some tires are very easy and some can be difficult. The funny thing is, I never know which is which until I'm done. I'm guessing that the more expensive machines are easier to use, but for the money, it can't be beat.
..........Paul