I'm with RGA and hifitommy. After 41+ years in this hobby I've come to realize specs mean little if anything when it comes to how something actually sounds. The first gear I bought (1967) was tubes and I was happy. In the early 70's I jumped on the SS wagon and quickly realized my listening pleasure was gone. So I went back to tubes. When I got my BS EE in the middle 70's I thought all wires and cables sounded the same and the improvements in SS gear made it sound as good as tubes. NOT!!!
By the time I bought my first pair of Magnaplanars in 1976 I was using a Dyna PAS-3 and 2 MK-III's. A couple of years later I got an ARC SP-3. Since then I've had nothing but ARC tube or hybrid pre-amps and tube driven planars or ESL's. Acoustat has been my speaker of choice since around 1983.
I don't read spec sheets any more. I use my ears and the opinions of people who have ears I respect. Tubes (to my ears) sound more like music than most SS gear. This is not to say all SS gear sounds bad. SS amps that are heavily biased to work in class A for more than 2 or 3 watts or pure class A sound better than other SS amps. The problems with pure Class A SS amps are heat, current draw from the wall and expense. However, I believe they are worth all the drawbacks because they sound better.

In short it's not necessarily how much distortion, but what kind. Even order distortion which tubes produce can be several orders of magnitude higher than the odd order distortion of SS and still sound better.