I don't have one of those Dremel or other rotary tools. I have a couple of jobs I could do if I had one and I'm thinking about getting one. So I thought I'd ask the brain trust around here for recommendations. So ...

What do you use yours for?
Is cordless better or does it even matter?
Are some too bulky so staying smaller is good?
Or, are some too weak to get the job done?
Are there brands to avoid? Cheapo ones that are excellent?

I really know nothing about these so I appreciate the input.