Concerning the cheap feeling of new MD units, I think that it is probably because new units are so light. I have had a MZ-R500 for two years now, and was afraid it was going to just cruble in my hands since the first day I got it. The unit has been great, never missed a beat, even after constant use and repeated drops to the pavement. I don't think these new Sony units are as bad as they are made out to be.
Actually, I'm glad they don't make 'em like they used to. I can't seem to keep the screws in my MZ-R30.
I think there are little MD elves that come out at night and steal them.
I've had to start locking it up at night...