Older road freewheels vs new mountain bike freewheels? I heard an interesting opinion yesterday that said all freewheels made back in the day (we were discussing this over a wheel with a Maillard hub and a Maeda (?) freewheel). The shop mechanic said that because it was made in the hey-day of freewheels, it was automatically better than anything made today, in which everything freewheel is being slowly phased out. Now I've tried out mountain/hybrid bike freewheels on a road bike, and I liked the ramps and such, but do the older freewheels (especially entry-mid level ones) really hold that much over modern freewheels? 

This may sound a little opinion based, but I'm know there's a factual answer out there comparing weight, usability, durability, features, and other technical attributes which make a difference to general, everyday performance.

Also, I'm strictly comparing members of the thread-on class, not discussing the merits of cassettes and free-hubs and other modern technology. I tend to run a lot of older technology by virtue of it being cheaper to pick up and cheaper to replace when my daily is stolen and cheaper to maintain myself.
I don't think old freewheels are "better" by default. While it's true that most of today's thread-on freewheels are junk, that doesn't promote the junk of yesteryear to "desirable" status. However, perhaps the median quality level was higher back in the day.

In the days before freehubs, freewheels, like most things, ranged from the downright awful to the excellent. Regina made brilliant freewheels, as did TDC and several others, but they command stupid prices on Ebay these days. And even if you can find a nice NOS example, it will probably need a rebuild to run optimally.

Obviously there was a much bigger market for freewheels 30 years ago, with a higher profit margin, so manufacturers could afford to construct them well. These days it's less economically viable even to invest in quality tooling, let alone top-notch materials. In addition, today's manufacturing trends have shifted further towards light weight, at the expense of durability. Our disposable culture doesn't consider this a great loss, I suppose.

Perhaps it's fair to say that the old freewheels were built to last, but the vast majority of them, even in great condition, would be considered "a bit rough" by today's standards, especially when compared to modern freehub technology. Sadly there aren't any really high-end freewheels on the market today for a fair comparison...

1970s Regina = Ferrari

1950s TDC = Jaguar

1950s Atom = Peugeot

2010s IRO = Peugeot

2010s noname = junker