If it were up to me, I would go Bermuda and throw rye down in the fall. It saves water ($$$) and Bermuda tolerates the heat in the summer. Mixing it with fescue should be ok, it will eventually choke out the fescue if it takes.
My wife hates Bermuda, she keeps telling me that she doesn't want brown Bermuda grass tracked into the house in the winter. I keep telling her that it beats red mud all over the place when the kids track it in during the summer b/c my lawn is dead.
I have no irrigation, which is a must have for fescue lawns. My newly overseeded lawn looked great until last June when we had something like 18 straight days of 90 degrees plus... it took two weeks to devastate my whole lawn.
The only issue I have heard with Bermuda and other creeping grasses is that sometimes neighbors get mad if your Bermuda spreads into their beautiful, heavily irrigated fescue lawn.