So it all depends on what you want to use it for. a VHF with AIS will have DSC as well. so.. kind of a win win in that regaurd. if you are looking to be able to track other vessels easier.. sure AIS is going to be the one for you. its uptake is glacially slow in australia "partually due to getting an MMSI number requires a VHF lisence and people are pretty....ho hum.. with getting to a course for a lisence" and partually due to Transponders being a bit more costly. it is and will be getting more easier over time.
Id forgo a vhf with built in AIS. in favor of a decent radio with a AIS transponder system. i can reccomend the Vesper AIS 8000XB if you want a solid performing unit.
alternitivly yeah VHF with built in class b AIS recieve is a cheaper option to go