My own view is that they're probably not, at least anymore. They were originally made in the US but now, as with so many other well known products the manufacture is "out sourced", in this case I believe to Mexico and from what I've read there have been quality issues. Mine died after two years despite not being used a great deal. I was never very happy with the flexible drive. After some research I subsequently bought a Proxxon, five years later it's still working fine and I'd fully recommend it, though I do not have a flexible drive for it so cannot comment on that aspect. They're not the cheapest but as has been discussed on this forum many times there is a tendency to get what you pay for, mine was made in Germany and my understanding is that they they still are. It's worth remembering that these tools have a fairly arduous life with the high speeds involved and the dust generated and I think you've got more chance with something that's been designed and manufactured to a standard rather than down to a price. If the flexible drive is an important issue to you then you could consider the rotary tools sold for use in the clock, watch and jewellery trades. These are designed for professional use and are accordingly expensive. Google "Foredom handpiece and micromotor" for info.
Michael