What about apartment buildings with good fundamentals, proper underwriting, 7-9 cap rates, that have $3-5k net cash flow per month.. any good argument to hold off on something like that?

You may want the money out for some seasoning time, so that the bank will consider that your money.Second, using loan as a down-payment gives you a lot of risks, as you are leveraging huge (the fundamental reason why banks do not like it).

The fundamentals don't change, just the scale and the number of numbers to the left of the decimal point. 

This is just a personal fundamental of mine that I have followed for 38 years.  

Fundamentals (population growth and housing supply) say prices will continue to rise BTW.

In several parts of San Diego, a correction seems plausible sometime in the next couple of years but there are other parts where fundamental indicators are still very strong.

Still best to go through the exercise before offering, though, and it is fun to confirm how close you are, though the appraisal will rarely come in over the contract price if it is worth more, but definitely will if it is worth less.Long answer to a simple question, but fundamental to understand IMO and hopefully practically useful for you ...

I agree with you fundamentally if you have to throw good money after bad though.

Everyone of success I have ever known, started by discovering this fundamental truth, that everything is just choices.

The fundamentals of the place look good, and I plan to rent both units out (I live in my own apartment).