Depends on loan type and will vary lender to lender too (especially when comparing retail and broker), not all have the same margins.

Ideally, I could choose a few cities to compare.  

There are three major ways appraisers look at value for residential:Market ComparableGross Rent MultiplierReplacementTypically, as it sounds you are aware, market comparable is preferred.  

February saw new listings increase significantly by 40%+ compared to this time last year.

the cost of the higher limits is minimal compared to the higher protection it provides the tenant (and indirectly to you).

I can give him $1,000 which is a sizable swing compared to option 1.

Here's time & money an agent or PMC needs to spend to get a rental listed:1) Make sure it's clean2) Hopefully, take professional pics and just not use the camera-phone3) Take room sizes and note positives and negatives about the property4) Since most rentals aren't advertised on MLS, research multiple sources for rental comparables to determine rent.5) Write a GREAT ad for the property6) Syndicate or manually enter the ad on numerous websitesThen, once published for rent, how much time do you think they spend taking all the phone calls (most of them from idiots who don't take the time to read the ad), doing all the showings, chasing applications & supporting docs, processing applications?

@Jesse LeighTypically a multifamily (2-4 units) has a higher cashflow compared with a single family home but will also required more work since you are managing more units/tenants with a multifamily.

However, they also dont COST you alot compared to a stick-built.  

AirDNA can be useful, but it is best used in areas where there is a lot of STRs to compare.