My parents have both recently done Ancestry DNA tests and I am the one who updates and researches my maternal line on Ancestry. We got two hints (one of which was rubbish, the other is a private tree) and 60 odd cousin matches.
The biggest problem I've had, after people simply not responding, is that a lot of the trees don't go far enough to show me the mutual ancestor. HOWEVER I have, with some investigation of the trees, found a few mutual ancestors quite far back, which has been a wonderful feeling because it feels like vindication that the research has been correctly done and the paperwork might be accurate. Even better, I believe I might be not far off proving the father of my illegitimate great great grandmother as I've got an ancestral match on her paternal father's line.
When the topic of DNA tests first came up I was sceptical of it- for one thing, I thought if someone said "your ancestors came from the middle east six million years ago" you wouldn't be able to prove you weren't being ripped off, but secondly if the results came back with "you have Scottish ancestry" I didn't like the idea that someone might grab the first possible Scottish ancestor they came across using that DNA as proof instead of other evidence. Since doing the test, I've found that with investigation things can be discovered and it has its uses.
I share my 7th great grandparents, Robert TREWARTHA and Ann RALPH with one result. I share my 6th great grandparents Peter BULMER and Elizabeth PIG with another result. My potential 8th great grandparents Nicholas UGLOW and Elizabeth SHORT with another result. My 5th great grandparents Alexander NELSON and Jane HUTCHINSON with another result...
... but those matches came because of poking around with the trees of my matches and looking for the links. Ancestry didn't supply them for me. It's unfortunate, but genealogy always has been a game of finding things out for ourselves.
I'm very much looking forward to narrowing down the guilty party who got my 3rd great grandmother pregnant and hope that with DNA we can at least get it down to one of four brothers.