Hi Peter,
Which AIS unit did you purchase?
The Comar CSA 300, the Digital Yacht CLA1000, the AMEC Camino 701, or the Furuno FA150?
I've got a Simrad NAIS400 Class B AIS currently, but am seriously considering switching to a Class A unit.
As best I can tell, the Digital Yacht CLA1000 is the Comar CSA300 with a different face plate. The manuals are identical, word for word. I've gotten good feedback on this device, so right now it's at the top of my list.
The AMEC 701 looks interesting too, but is less proven, and I'm a little worn out on experimenting with new products at the moment.
The Furuno FA150 is the most proven, but it is physically very large. The control unit is the size of a small suitcase, and I'm really running tight on space.
The tough part with all of them in interfacing them into a system that is otherwise N2K. The Class A devices are IMO compliant, so not dependent on N2K. In fact, only the AMEC even has N2K, and it is output only.
There is a whole other post that could be made about the issues of interfacing in a mixed N2K and 0183 environment.