Being a SS owner and user, I rely a great deal on specs to gain some initial understanding as to how an amp might perform in my system. This isn't a fool-proof method, though. To quote some of NAD's marketing, "people don't listen to specs."
When I have entered into conversations about amps with tube owners, the topic of specs invariably comes up and is greeted with "ah, I see you are a SS guy." I don't fully understand what causes that response, because tube people have to be somewhat concerned about ...
The problem with specifications is that they don't say much as to how an amp for example will sound. This is easy to verify - put together any two amps of similar specifications but from different sources, and in any half decent system you will hear differences not reflected in the specifications.
On the one hand, this is partly because to this day, after 37 years in audio (I got hooked really young, at just 13), I have never yet seen a fully specified unit. This would include, for example, its immunity to RF breakthrough at one or more given frequencies. Before anyone says I'm on hard drugs talking about RF in audio, please remember that strong RF influence, even if its well into tens of megahertz, can work its way down into the audio range through plain, old fashioned intermodulation NOT reflected by classic specs.
On the other hand, there's always the question how such specs were obtained. For example, an amp said to have 0.1% THD could sound better than an amp said to have 0.001% THD if the first amp has a very low feedback factor of say 10 dB (3:1), while the second amp has been raped with a feedback factor of say 60 dB (1,000:1). BTW, the above example actually exists.
Lastly, we should not mix our priorities here. If we cannot measure and quantify something, that does not mean it doesn't exist. Thus, we should not rule our ears according to measurements, but rather it's our ears which should drive towards better and more meaningful measurements.
This from a guy who uses a lab full of measuring and test gear, a solid state guy. How low can you go?

Cheers,
DVV