I have two of them, and they're my preferred way to move machines around. I wish they had bigger wheels on them with some tread to deal with obstacles better, since the tiny wheels get stuck a lot on concrete seams, floor mats, pebbles, door frames, etc. When the wheels do get stuck while you're pushing, the machine will slide across the frame while the dolly remains stationary. That can sometimes cause some excitement and exertion.

In short, I don't "love" them but they're the best tool I've found to allow one person to move heavy machines.

True, and I've thought about it before but haven't done it. It's one of this things that you want to do in theory, but the current solution is "good enough" and there's always a more-pressing project. When the existing wheels or casters wear out that will force my hand.