High speeds and minimal load on the bit(s) are the 2 secrets to using any kind of Dremel tool.

They're not meant to replace a 4" handheld grinder or an 6" bench grinder, people who keep that in mind will usually have a lot more success using them.

I've got at least 4 of them that I can think of, couple of battery operated ones that are nice for quick and easy jobs, I've got one mounted in a little drill press/stand that Dremel still sells, great for lightweight work.