I have had OK luck with the MZC series and have really reliable control of them through their RSA 232 adapter.

For the doorbell I use the Niles DBI-1 doorbell interface. It has two contact closures and each can be set to one of the 6 or 8 pre-programmed doorbell tones and it has either a contact closure or 12v output trigger. This unit feeds the doorbell input of the MZC or an unused input on the B&K and the 12v trigger initiates the doorbell sequence in the multiroom controller to switch to the door bell input for 3 or 4 seconds and then back to whatever it was doing.

If you have a choice, I would take the B&K over the MZC, Russound, Xantech, etc Chinese manufactured multiroom system in a heartbeat any day of the week.