Here;s the problem… Ancestry is owned and operated by the LDS (Mormon) Church, here in the U.S. It is a fact that they have the most complete genealogical records anywhere in the world. For a long time it was more American centered, but over the years it has gathered an unbelievable collection. It's based in Provo, UT… home to Brigham Young University and nearly more of a center for Mormonism that Salt Lake City...
As an aside, they have a huge… huge storage site up Cottonwood Canyon just east of Salt Lake City, Utah. I've been past the entrance a number of times. It is well guarded and unapproachable and the entrance is two well constructed steel doors capable of withstand all but a direct nuclear attack. (It's part and parcel of several aspects of the church for the most dedicated members).
At any rate, most of the other available sites rely on the LDS collection for their own data bases. They expect to add to their collection from subscribers.
Additionally, since FamilySearch has been mentioned, here's a recent article on the agreement between Ancestry and FamilySearch…
http://www.heraldextra.com/news/local/central/provo/ancestry-com-joins-forces-with-lds-owned-familysearch/article_4ce0e3fc-067a-5546-8f00-a0d0e111033a.html