There’s a new generation of fixed DSC/VHF radios incorporating an AIS receiver that are seriously worth considering.
The clever bit is that they combine excellent radio performance and AIS receiver functions in the same compact unit. An internal splitter shares the radio and AIS reception from a single VHF antenna.
The not quite so clever bit is that the display for the AIS information is really too small to be practical in areas of high ship traffic, which is when you want it. However, what you can do is connect the AIS output to an external plotter or dedicated AIS display.
Remember that you’re depending on a single antenna system, so it better be a good one – obviously that’s going to be a Metz Manta with top quality coaxial cable. And it’s always a good idea to carry a spare antenna with a means of deploying it in case you lose the main antenna through a dismasting or other emergency.