I haven't had a lot luck finding my relatives on Ancestry.com. My six month trial is about up and I'm debating on whether to go another six months. I particularly hate searching for "John C. Brown, born 1830 Illinois, married 1850 Illinois, died 1890 Illinois," and being presented with choices of people who lived and died in other states and other countries, World War I draft registrations, 1940 census results and so on.
Today I searched from my genealogy program (Legacy) to FamilySearch.org. I was not expecting much. However, they seem to have improved their search. The results were a lot more relevant than those I've gotten from Ancestry. I found some census images (specifically 1850) which were sharper than those I had saved from Ancestry. I don't know how widespread the better images are but I plan to check.
Fortunately FamilySearch is able to use logic in the searches. Volunteers transcribe documents and those transcriptions show up in the search. The volunteers are working with old images and rotten handwriting in some cases. Some of the transcriptions are quite accurate. Some of the transcriptions are hysterical, so obviously incorrect it is pathetic. It reminds me of some of the 1940 census arbitrators' "wisdom." But FamilySearch finds that and that's what counts.