Specs are good for the ones who know how to understand them, and of course there are parameters inside the specs that are consider standard, good or bad, but IMO the specs do not give you any idea of how a given device will sound, in other words I have heard amps that measure like champs, and sound like crap, and others with worst specs sounded far better...
Just an example how many times we have seen tube designs with a THD of 1% or even worst, and comparing them with others with a lot less, and we prefer the one with higher THD...
IMO it is not a matter of the specs alone, but a combination of them, and also sometimes the specs are not clear or very specific as what they are actually measuring, in the case of the THD, just to mention one example, we have harmonics, a sum of them is not an indication of the sound as we all know, some harmonics are more pleasant than others to the ear...
My take in that, is that measurements right now are a gross approximation of a performance, but IMO we need to go deeper into them to understand what they really mean, and how they were taken...