At least I know it's sitting on their credit report and preventing them from harming someone else.

I am nervous to furnish it then have it sit empty. 

I don't know him personally and I haven't used his product so I can't sit here and give you an honest review.But what I can say is that this statement from his sales page is very suspicious.

You will always, ALWAYS have to manage the manager UNLESS your a-ok sitting back and accepting whatever you get for a result, good or bad. 

They've got a travel trailer sitting on the septic for the time being.When we reached out, owner simply said they needed to hold off on selling it until next year b/c they sold their primary residence this year.Don't know much about tax implications of selling primary residence in the same year as a rental.  

how long do things sit on the rental market?

They are sitting atop a mountain of motivated sellers.  

It sits on their credit report for up to seven years. it's a warning to other landlords and prevents them from qualifying for a home loan, car loan, or credit card.I've had some tenants sit in collections for years, then pay everything they owe because it was stopping them from doing something.You should consider a new PM.

Where I'm stuck is whether I should use a metering system that pre-prints a stamp onto the envelop or find a machine that can place a physical stamp onto an envelope (obviously I can't sit there all day stamping).I'm thinking from the perspective of mail that looks to "businessy" vs. mail that looks more personalized for better response/conversion rates.

I realize it's free money just sitting there I could be investing.