I have NEVER gotten call back inspite of indicating that I was a willing seller in one of the hottest markets in the country.So, my questions are:1) Do these companies get leads then sell the leads to whoever will buy them or are they already contracted for a specific buyer?

First off, I knew what I was doing and didn’t need the help of a buyers agent.Second, in spite of the fact that the sellers agent has a fiduciary responsibility to the seller, the fact of the matter is they’d get both sides of the commission if I was the buyer.

I think it's also important to mention here that Boston, and other larger metropolises, deploy a tenant oriented brokerage fee meaning that the renter actually pays, not the owner, so in spite of the service being virtually free, you do not see the value in having someone represent you and executing on the rental of this unit. 

The seller is not providing lease copy of the tenant inspite of multiple requests.

Respecting their wishes of getting rid of it ASAP in spite of price.

We’re hoping to build one this year in spite of that.

Or would I get more bang for my buck marketing it on Airbnb, VRBO, etc, in spite of needing the short term rental permit and hotel tax and so forth?

I know of a bank that, in spite of the above, somehow interprets it such that they will not let ANYONE use a 401k loan, no matter what, even though that guideline is crystal clear (to me, at least) that you can (solution: I simply don't broker the loan to that bank if that's the scenario we are working with, and I'm not even going to waste time with them if we're doing something along the lines of what is being discussed in this thread). 

This was in spite of the fact that we had verbal confirmation on the phone the day before that they would be there.

People, including relatives of mine (in spite of being born abroad themselves), often seem terrified of putting a single cent of investment into non “first world” countries.