The only time I might even remotely judge someone is when they approach me and try to compare. Sometimes I am shown things that blow me away and I'm like, shit, I need to go get tattooed by that person. Other times I feel a bit baffled that the person doesn't see the difference between some of my tattoos and theirs (not all my tattoos are great, but I learned early on enough who to seek out). So, I suppose it isn't as much judging as it is trying to understand that persons level of cognitive comparison.
That said, a lot of my friends are tattooers, and I cherish the tattoos I have from them even if they aren't great (and I will probably get more). The other day when my friend Chris tattooed a small dagger on me, he also thanked me for letting him tattoo me during his first year of tattooing. He knows I've covered up one of the ones he did, but I'll forever keep the black Viking from Malone flash. It looks spotty, but it's as much a portal to his past as it is mine.