Assuming the OP is looking at used rats as his post implies and not off-the-shelf new. I'd also assume we're looking at lower profile heads than the typical round head that for me never fell under the category of 'coarse' tooth....
I buy and sell used tools, including ratchets, and often encounter older ones. I've played around with using many of them. There's a few mentioned I've never encountered for some reason like the Armstrong or Williams. Of those I have, a few observations:
The Proto/Plomb/Penens design seem to have the least backdrag and once cleaned and lubed are among the smoothest I encountered. Some call them tic-tocs, I call them V pawls. However, I must also say that I've encountered an inordinate percentage of these that are just plain worn out, more so than other makes. I'd also include here the early 1950s Allenite, a Japan knock-off of the P/P/P tic-tocs, every bit as smooth and powerful. For me, though, the tooth counts are just too low.
The older Snap-ons I find almost always need some sort of work whether it be exceptional-quality lubrication, playing around with the spring, or in need of rebuilding. My Dad had some M series (military, but the mechs are the same as public sector product), and I was kind of surprised how many rebuild kits and older parts he had laying around for these until I started using the ones he gave me. Almost a situation that, because they are Snap-on, one finds one's self making excuses for them. One could debate as to why this is so, but I'm only reporting what I've experienced.
New Britain and its derivatives (not the Kilness, which is a round head, but the teardrop or pear style) seem to be solid ratchets, but to me always have excessive back drag. I'd lump Walden in with these too, which seem like a solid rat but the mech and finish just strike me as unrefined.
Craftsman--just don't like the CM philosophy behind any of their ratchet designs and executions. They are a 'use if I must' kind of thing.
The Duro/Indestro seem to be consistently nice in both the feel of the mechanism and the grip. They are kind of pedestrian to look at, but I give them high scores on what really matters. If I had to use a CT for a living, I'd lean heavily toward these, if it weren't for.....
The Cornwell coke bottles. There's something special about them. If I had to use one for a living and could only choose one alone, I'd have to tearfully say farewell to all those about which I find something endearing and go with these.
That's my read on it. Your mileage may vary.
