I have a fair number of WDC's. They run the gamut in terms of smoking and fabrication quality. Their worst efforts were akin to those Chinese junkers you see offered for a few bucks and about twice that much in shipping on eBay; their best could rival the finest efforts of the best contemporaneous English makers.
This is as you might expect with what used to be the world's largest pipe maker who was in business for many decades.
Here are some "for instances":
1. I have a couple of their "theme" pipes, mass-produced for non- or casual pipe smokers. One is a 1927 apple sort of affair, carve-blasted with a crude approximation of an "aeroplane" and bearing the inscription "Lindbergh, May 10, 1927." Another, from 1937, is vaguely Dublin shaped and bears an eagle and shield design. Both are small and made of indifferent quality briar. I'm smoking them a lot in an effort to flog them into being some kind of acceptable smokers. Neither had been smoked much when they were new.
2. By contrast, I have a sterling-banded yacht "Windsor" from the 1920's. It came to me heavily used and really ugly, but with a thorough spiffing job, I wound up with a beautiful pipe (birdseye sides and cross-grain front and back, no fills or pits) that smokes wonderfully. After I scrubbed the decades' worth of gradoo off the outside of the bowl, it buffed up to a fine luster on a new wool wheel: the original carnauba wax had survived! The stem came superficially oxidized, but cleaned up easily and is of the same quality vulcanite as what's on my 1925 Dunhill shell.
I also have a cased "Triangle" yacht with a deep red bakelite stem from the 1930's. It too had seen many pipefuls but had been decently cared for and was a simple matter to restore to smoking condition.
Both of these are lovely smokers which compare favorably with my 1937-or-before GBD Xtra or my 1921 Ben Wade Leeds apple. They're different from their contemporary English pipes, but it's more a matter of personality than innate quality.
Finally, I have an amber-stemmed, gold-plated brass-trimmed bulldog from the 1890's that's out getting a replacement stem. I have high hopes for this one: I've never seen such tight, straight, perfectly aligned flame grain on a bulldog of any manufacture or age. With a new stem and the smoke-path opened up, it looks like a natural for Squadron Leader and other mixtures of that ilk.
It's unfortunate that they didn't seem to mark grades or line names on about 98% of their pipes, and they weren't consistent even when the did do this. But there are some things to look for for a quality WDC of almost any period:
1. Fancy stamped brass or gold-plated brass on rim or ring. This treatment seemed to have been reserved for their best.
2. A case that fits the pipe.
3. A sterling silver or silver-plated original band on a bowl with no pits or fills.
There is one peculiarity of older WDC's, before about 1940 (exception: the Wellingtons), and that is the small-diameter smoke path. You'll need a long drill bit on a handle to carefully ream out the smoke path in both shank and stem.
But, following these guidelines, you may well be able to find a quality WDC of ancient vintage that will give you a most satisfying smoking experience as well as being a nifty piece of Americana.