The other problem with COC is that it is easily manipulated. What is the COC on a house you pay cash for vs a house you finance? The cash in for the first example is clearly higher, but is it better deal? If you renovate the property in year one, what does the COC look like? What if you leve the building vacant for 6 months while doing the reno? Don't do anything, delay all maintenance, COC looks great. If you are someone likes to consider, cap ex, repairs, reserves and vacancies, COC falls apart there as well.
There are very few REAL number in real estate. The rest are derived from the REAL numbers and even those become less meaningful over time. I like gross rent multiplier, how much the property produces compared to its costs. It allows a comparison of the performance of dismissal assets. The second number I like, is how much do you have left after paying actual expenses, not the "could be" expenses. It is difficult to normalize future expenses on an old building vs a new one.
The last part is a little squishy, what is the area like? The more depressed and rough the area, the higher the return. Ocean front real-estate generally has horrible cash flow.