I refer to my Dremel as the "lotta dammage real fast" tool since you can really screw things up with one really quickly. But, having said that, I wouldn't give mine up.
The cutoff wheels are just awesome -- hands down the best Dremel bit. These things cut like a hot knife through butter (obligatory knife reference).
Just a few weeks ago, I had yet another phone line put in. When the technician arrived, he needed to get into the service entrance box which I had locked with a paddle lock. I couldn't find the key anywhere. Since this guy is costing me $65/hour, I wasn't gonna look long. I whipped out my Dremel and cut that hardened steel shackle in less than one minute.
Like everything on a Dremel, the cutoff wheels take a bit of practice to learn, since they shatter easily.
Forget about the cloth polishing wheels. They fly apart spewing threads everywhere in a matter of seconds. Maybe I've been doing something wrong, but that's been my experience. The felt wheels work nicely, though.
The Dremel is really a very primitive tool. The skill/art is entirely in the hands of the user. It takes practice to develope a good touch with a Dremel. Don't start on anything you're not willing to destroy.
The Dremel has no safety guards (this is a tool from the same era that brought us lawn darts). So, be careful and wear good cloths. I have Dremelled my leg and my hand more than once (nothing serious, thankfully). Oh, and always, always wear eye protection. The grinding bits can explode, the cutoff wheels shatter, and any bit can break.