Great summarization by 萬楓.
Cap Rate is the overall frame. Cash flow and return on equity can be controlled by the investor. For Cap Rate, some costs may be controlled but the price is fixed when bought. The rent can vary but relatively stable, not much adjusting.
Mortgage can be refi-ed and how much leverage to be used associated with risk. I read some posts not long ago mentioning some Lao Da(s) keep LTV in a fair ratio like 50% or so.
