I think it depends on your personal investment strategy and what you want to accomplish but I've pondered the same question and I think overall, SFH is the way I'll go. There are a couple of things that you haven't mentioned that steered me toward SFH.
Taxes & Insurance are higher on MF which has an impact on your cash flow. You also have issues of tenants impacting on each other, for example, two tenants not getting along or one neglectful tenant damaging the property and affecting the others.
I heard a story the other week about a horder tenant in a duplex - it wasn't pretty. SFH requires less "management" too, calculating utilities, waste etc. if much more complicated with MF. You also mentioned vacancy being a pro on a MF, but it can also be a massive problem. If something bad happens to a property and you have to vacate the building, you lose a whole chunk of money.
MF has it's place, and I think if I was buying a Duplex to live in one side and rent the other I'd take it on, but ou have a lot more to consider and do with MF than you do with SFH.