I have an older one and am curious to know how the horns they're turning out these days play....solid right out of the box? needing more than minimal setup?
This response may come too late for your purposes, moontom, but...... Just bought a 66RUL new about a week ago, and am in 7th heaven. S/N 5107xx. If it sat on the shelf, it may be a year or two old, I dunno. After having played a good bit of classical and jazz from age 7 through college, I had not owned a horn for 15+ years. The last horn I had for any length of time was a late-60s Mark VI soprano on loan for 3 years during college. Happened past a chain music store in Maryland and, on a lark, asked to borrow a mpc and play the oddly dark-looking horn I saw hanging on the wall. Had not even heard of P. Mauriat prior to that evening (yes, that's how out of it I had been!) -- I chose it purely out of curiosity. I was completely blown away by all aspects of the horn -- tone, ease of playing through all ranges, responsiveness, and, most of all, incredible controllability. It did anything and everything I wanted without me having to try hard -- I could whisper, I could project, anything. I simply thought of an idea, and it would pop out of the horn.
I researched the Mauriats online and found many good reviews and happy owners, but I had my doubts about buying a horn that had not been set up by a pro sax shop.
Went back and A-B'd it with other horns, including a 66RDK, a Yamaha 82Z, and a Kessler Sonus, which is marketed as being better than a Mauriat for less money. None of the others had anywhere near the total package that the 66RUL had. Intonation was a tad more perfect on the Sonus than the 66RUL, but the 66RUL's ergos, robust build quality, and much better consistency of tone up and down the horn made it my clear choice. Had to go with the horn that was going to continue to give me grinlock all the time.
I've seen a few posts about build quality problems with Mauriats as recently as late 2013 on SOTW. Perhaps I was particularly lucky and stumbled upon one of the better examples of a 66RUL, as it was not set up and yet played great out of the box. But I haven't found a single flaw or problem anywhere on the horn. It appears to have been designed well, manufactured with care, and, with the possible exception of what seem to be plastic-tipped adjusters on a couple of keys and levers, built tough and built to last. (Perhaps the plastic has some function/value, I don't know -- I'm not a technician.) And I really like the look and feel of the unlacquered brass.
Bottom line -- I found no drawbacks, and no flaws. We'll see how it holds up to use over time, but it seems like Mauriat has only gotten better at what they do. And I can't seem to put the horn down! What else can one ask for?! Highly recommended.