For me, a low-value numeric id has never been an impediment. Aesthetically you might lose a small amount, but many of us use surrogate indices in our databases

For me, a low-value numeric id has never been an impediment. Aesthetically you might lose a small amount, but many of us use surrogate indices in our databases and it fits well with that design pattern. The backcountry example smacks of overzealous in-house SEO to me - the observation that Google (in particular) tend to favour the lower level of structure could lead to choosing that output, but ignores that the first three levels appear to hold comparable weights. I'm not convinced it would offer much benefit. Matt Cutts has indicated in the past that 'natural' levels make sense, maybe 3-4. First level entries do have use (see the 'enhanced' results for some sites based on sitemap priorities), but having 100s of them will likely remove this useful trigger. From a technical standpoint it's definitely creating obstacles. You create an additional layer of restrictions in the database index. They must have a table of unique level-1 indices. So if there is a brand that corresponds to a generic term (not great for trademarks, but it happens), you will get a uniqueness collision. It seems well executed, and no doubt their CMS input will inform them of clashes, but for me this is genuinely not as useful as a 'breadcrumb' structure from a UX perspective. They've essentially introduced complexity for the sake of an assumed SEO advantage that my anecdotal evidence can't support, and in doing so have lowered the utility of their urls, per the principles (of which I agree) of the parent article. That they're buying the term "smith phenom goggle" from adwords, and are stuck on page 2 of the SERPs might back this up.