DNA has confirmed a couple relationships that have been assumed for many years but for which no paper trail has been found in a couple iffy spots. So that is helpful.
My best success with DNA was with someone that I have a significant match, but no "obvious" connection to their tree. I found one surname after looking at all 8000+ names in the list, but it was still not someone that I was researching.
BUT, when I saw that person's spouse's name and her parents AND looked through some of my spotty research on the surname of interest I found them quite connected through wills, guardian records, etc...so I had the paper trail but didn't know what to do with it without the DNA match.