Specs are interesting in the abstract, and can be useful for comparison, but caution is in order. First, vintage machines claiming otherworldly specs were built during a period of vinyl supremacy and a specs 'arms race', such that companies, especially the Japanese, made a big deal out of claiming ever-better specs. Second, those same machines are now 40-50 years old, so who's to say whether the examples any of us end up with can come close to such specs anymore?
Now, can the human ear hear the minute differences claimed in W&F? Maybe. I'm skeptical. Still, there is much to be said for the technologies advanced then, and by the choices they result in for the consumer. Does it matter then that a DD can produce tiny W&F? Yes, if only because it offers choices for the buyer, and because many of those old machines can be had for very little money these days. By the same token, my informal measurements of new budget machines, using a cellphone RPM/W&F app, have yielded numbers that are better than their specs called for.
FWIW, in my experience with machines new and old, belt drive and DD, budget and not-so-budget, I have yet to hear noticeable W&F, although I DO hear differences in noise floor. FWIW, my U-Turn Orbit, a budget keeper IMO, publishes a S/N spec that seems wildly optimistic, considering it uses a hard-mounted motor that obviously adds to the noise floor. So a focus on specs, for my use and hearing capacity, isn't helpful.
I began in the hobby by searching for new machines and value, so I started with the typical budget machines we read about, slab plinth belt drive and DC/MDF/belt drive examples, of which there are many on the market. I tried a new Super OEM DD, I tried a moderately-excellent belt drive with very good specs, and have recently found my way to old suspended belt drives.
Every machine I've used has proved excellent in its own way. As a new hobbyist who required value and simplicity, or would have simply not entered the hobby at all, the U-Turn Orbits and Fluance machines were great in providing good sound and great value. For the hobbyist who stops there, do specs matter? Not IMO. For those of us who are 'in for a pound', there is much to explore, but I still wonder how useful specs are along the way. Can I say whether my two Thorens machines are anywhere near meeting OEM specs? Hell no. Did it matter in the end that my DD turntable provided fantastically low W&F? Not really, for my ears.
For hobbyists like me, the next stop on the journey would be machines like the VPI Scout / Prime, or the Rega Planars 6 or 8. Again, do specs matter there, knowing that machines from VPI and Rega sound very different and that Rega is famous for being off speed from the factory? Not to me. Specs are for the marketers and they were weaponized to differentiate during the heyday of vinyl, but for me aren't particularly useful when making decisions about machines.
