@Marc Weisi
I love your post and you make some great points!
However, I will have to respectfully disagree with your overarching opinion.
(Side note, my background includes some experience as an acquisition analyst for a company that owns 10,000 units across 10+ states and I personally currently manager 1,300+ units for that same company. So, I know all about IRR, CoC and various other metrics to decide if a property is a worthwhile venture.)
I think the most basic and important metric when discussing a market is cap rate. It is the quickest and straight way to see what investors appetite for risk and reward in a given area is.
You are correct that you can’t decide what deal to buy based on a “cap rate,” but it does give you an idea of what returns you should be aiming for in any given circumstance. (An area that turn key assets sell at a 7% cap, you may want value add to be able to get you to an 8% or 9% cap.)
Also, regarding how to calculate cap rates I think it fair to assume most people are somewhat in the same ballpark. Yes, if someone claims to be getting crazy high returns they likely are just including taxes and that’s it. I think most people on bigger pockets are using some variation of what they saw in Brandon Turners many videos...
Lastly, when determining what something is actually worth cap rate is the only true metric that says what it is worth to everyone. The IRR that one person may be able to get is different than another (partly due to financing and partly just how they decide to underwrite appreciation). Cap rate tells you if you paid in cash what returns would investors want NOW. In Manhattan (pre-Covid) people would be willing to take 2-3% cap rates (which means with financing a negative return) because they Project a 20% IRR with appreciation or just think it's a safe place to park money. Another market they want a 7% cap.
***At the end of the day, Cap rate is the most important metric when evaluating —a property within a specific market.***
It should not be the only metric used to decide whether to buy a deal (unless you pay all cash for turn key ;) )