I've got news for you guys:
when comparing to used Leica lenses, the Hexanons are not "well-priced", at least not anymore. > US 500 (the last one in the classifieds) for a 50/2 is not cheap at all. If you want bang for the buck, try a good copy of a Canon 50/1.4 LTM which runs circles around both Hexanon and Summicron, at least at f1.4 🙂 My last 50/2 Summicron copy cost me US 50 (an OM Zuiko 50/1.8). The ZM Planar usually runs around US 500 as well. The last good v4 28 Elmarit I saw cost < US 900 on ebay, just about 20% or so more than one pays for a clean Hex 28/2.8 these days. And you have to be well off and/or very dedicated to shell out US 1200 for a UC Hex 35/2.
That being said, I used 50/2 and 90/2.8 M-Hex, and (a) found the built quality very good, and (b) the 90/2.8 quite special and beautiful in terms of signature - as Ernostar coming closest to the Hasselblad teles that I know (150/4 on 6x6). The 50/2 for me felt like "just another 50" ... Nothing special and comparing it to the Summicron, a design from the 70s, doesn't help either ....
Cheers,
Roland.