Welcome to BP @Peter Perreault,
Negative cash flow and betting on appreciation vs. positive cash flow not counting on appreciation is a controversial topic on BP.
Your idea of living in the first multi-family property investment is called house hacking.
Here are a few articles I found just on the bigger pockets website.
https://www.biggerpockets.com/renewsblog/2013/11/0...
https://www.biggerpockets.com/renewsblog/2014/11/2...
Bp podcast 94 and BP podcast 86 also address house hacking but I haven't watched them yet.
Which part of San Diego are you looking?
My personal opinion (could be wrong): the housing market has been doing very well the last several years and maybe is just starting to slow down. I anticipate we are going to start seeing better investments with better cash flow popping up more so in the near future than now. If I were you I would not invest in something with negative cash flow because we are investing to make money not to lose money. (I realize you may save a bit on rent now, but in the long run it may not make sense because appreciation may never happen). I would wait to find a really good deal and then race to the sky from there.