The Alliance was formed earlier and has always been more liberal on matters such as women clergy and homosexuality.
It has about 130 affiliated congregations, largely found in metro areas, particularly on the East Coast. The largest number of congregations are in North Carolina and Virginia.
The Alliance has an "ecumenical partnership" with the United Church of Christ and the Disciples of Christ, and some churches are affiliated with those denominations, as well as with the American Baptist Churches-USA.
The Alliance has a very loose structure, preferring partnerships to recreating denominational structures of its own.
The Cooperative Baptist Fellowship is larger — about 1,900 congregations — and was formed later than the Alliance. My observation is that the CBF was formed by Baptists who were unhappy with the way the SBC was going but were 1) too conservative for the Alliance and 2) wanted to recreate a denomination along the lines of the SBC.
Thus I would view the CBF as a protoconvention, which has its own publishing house and missionary board, yet has been denied the full trappings of a convention by congregations that don't want to go down that road again. It is a partner in several educational institutions but controls none of them, for example.
The two had some discussions about merging early on, but nothing came of them.
The Alliance is "welcoming and affirming" of homosexual relationships; the CBF has no official stance on homosexuality but "does not allow for the expenditure of funds for organizations or causes that condone, advocate or affirm homosexual practice. Neither does this CBF organizational value allow for the purposeful hiring of a staff person or the sending of a missionary who is a practicing homosexual."
Both support having women in ministry.
A good number of Alliance churches also are affiliated with the CBF, but given the sheer numbers, they are a minority within the CBF.
Sometimes, given modern Baptist polity, it is hard to sort through the welter of affiliations because they are not necessarily exclusive.
One example I'm familiar with is First Baptist, Oklahoma City. It is affiliated with the CBF and left the Southern Baptist Convention and the Baptist General Convention of Oklahoma (the statewide SBC organization). Yet it remains a member of the Capital Baptist Association, the vast majority of whose member churches are Southern Baptist. (And, though they are technically autonomous, some Oklahoma Baptists will tell you that the associations function as subsidiaries of the statewide convention.)
Another example, picked almost at random, is Calvary Baptist of Roanoke, Va. It is affiliated with the Alliance and the CBF (and the ABC-USA) yet is also affiliated with the Baptist General Association of Virginia, which itself is associated with both the CBF and the SBC.
Of course, a good many churches are affiliated with both the SBC and the CBF, although dual alignment has been slowly waning in the past few years.
I appreciate the spirit in which you asked your questions and would remind posters that this is a fellowship forum, not a debate forum.