A last comment I could make would be that a part like the ADG714 has an I2C interface on it so it is very easy to provide a 2-wire interface to the part from the microcontroller. In some applications that can make it much easier to locate the part in the analog section of your board and minimize the number of signals you have to couple across the digital to analog boundary.

I just realize, that you do not only have much experience in digital circuitry, but also in analog electronics, Michael.
Beside the saving of number of signals when using I2C interface, there is also some other big adavantage: I2C signals are slew rate limited and produce much less high frequency noise over ground routing. This is especially important, when extremely critical ground connection between analog ground and digital ground is involved.

Bye,
Kai