The only downside seems to be that it is more computationally-demanding to calculate.I have a few questions related to this: 1) Is this the only con to using FMRR instead of MIRR?

The tenant does need to have some kind of Internet access to do this - they can do it from a computer, phone, or tablet. 

[Not related to the substance of the post, but in case anyone wondered]Moore's Law: Every 1-2 years, computer processing power will double.Murphy's Law: Anything that can go wrong, will go wrong.

But on my commutes to and from work, on my breaks and lunches, and on my weekends when the kids aren't up I'm studying like a mad man, shoot, even when the kids are up I'm usually sitting in front of the computer with them on my lap as I explain to them the various ways to buy and finance real estate (getting them started.I've read 10+ books this year so far.

@Kyle Ropelato - I'm not in front of my computer but when I am I will send the spreadsheet I use to evaluate my deals. 

I can't tell you how many times wholesalers have quoted me ARV values using Zestimates.Zestimates use an automated computer algorithm to try to determine price, the problem often comes into play when the website pulls comps that aren't really comparable. 

@Nathan ScottIt's possible to compute the rental vacancy rate for various markets within the country by using data from the American Community SurveyThe formula is as follows:The rule of thumb most investors use when underwriting is 7%. 

Being in person is completely different than an over-the-phone/computer relationship. 

It's all about managers not being able to get their head around the fact that you are an adult and the work will still continue to be done if they can't see your computer screen.

I do have a three step plan to help you solve this problem: Step 1: Open your computer and navigate to your preferred search engine.