We had 3 of these drop on one adventure with a mid 40's level group. 2 dropped off named frogs and one off of a named elf. Kinda par with Polished Tin Mail if you ask me, just a little less dex and more stamina. We also had a 4th named on this mission who dropped a Grainy Elven Band... 4 named and 4 augments over all plus 10AP when we finished. I hope I have more adventures like this one.
Regarding the comments about it being on par with the Polished Rin Mail, I'd say that Polished Tin Mail is definitely more preferrable. At least, it seems that way.
I won the roll for this armor after an adventure (nobody in the group could wear it), and haven't been able to sell it in the Bazaar. (This was about two weeks after LDON went live) Its still on my trader, gathering dust.
Probably a good item if you have worse and can wear it, or a decent item to twink an alt with, though.