Nearly all homes in this area use the Symmons Temptrol valve -- as far as I can tell, they're still all made right here in Braintree, MA, USA.
They have one control for the temperature and one lever that controls how much water (volume) and where it goes, tub or shower. I've never heard anyone who had trouble with one of them, although I'm pretty sure, as these things go, that someone probably had to change one of the parts that wear out inside after a few decades.
The vast majority of the complaints I've heard (recently) regarding this valve (which BTW, costs less than two hundred bucks at HomeDespot) have to do with the fact that the valve seems to limit the shower (but not the tub) faucet to some 2.5 gal/min and if your shower also has a limiter inside, it may prove too much, remove the limiter from the shower.
It doesn't look as retro as a 2-handle valve assembly, but honestly, homes were built with these as original equipment in the 70's if not 60's and before, so it will not read as modern as most of the other offers.
And, to be honest, I vastly prefer to have this valve in my home and shower in comfort even if someone uses a toilet and/or other faucets at the same time than the couple of places I've been to with the 2-handle faucets and the scalding/freezing shower "surprises".
It is true that a properly sized and installed plumbing system will not suffer these "surprises", but it's also true that a properly sized and installed plumbing system is both more expensive and harder for an inspector to make sure won't scald someone.
Pressure-balancing valves are a good compromise, in my opinion and worth the extra safety/comfort they provide. And while I will readily agree that most of the offers lack something (even the Temptrol II has the problem of letting you choose a temperature but not the volume of water), the truth is that you can still find good valves that will do everything and still cost less than the fashionable stuff out there for lots of money.
Cheers,
-- Paulo.
