Dremel do seem to make a good quality fundamental tool. (The motor and collet in the Dremel body). Some of their bits also get praise. But the various Dremel devices for "adding-on" are made down to a price and never make it up to a high quality. Dremel motors seem to last - although you can always find the 1% of complaints that say, "Mine didn't". They seem to have precision and resilience in the bearings, going from my own use (originally of a corded version but now of the cordless kind).
One does have to keep in mind that they are relatively low-powered and not meant for big tasks. But use them for their intended purposes and they're very handy and versatile things to have.
If I was buying such a tool today I'd probably buy the Bosch Blue 12V version. These tools are well made and form part of an extended range of cordless tools that take the 12V battery. I have several of those and find them just a bit more thoughtfully designed than a Dremel. But there's nothing in it, really.