Have a calculator that shows this as well.What is boils down to 99% of the time is #3 and that persons ego / fear of giving someone else $.

My personal opinion of values is that if you're looking to get a predictable return on investment that you would be better off buying a legal duplex.

I have 7 doors personally and another 4 with a partner in a two member LLC.  

Personally, I am not a Detroit guy, just pointing out actual facts.

My personal investment philosophy would avoid leveraging my primary residence unless I had plenty of reserves to ensure I would be covered in that kind of situation.

Key differences for us include:- we JV with local person on our deals.

It's allowed me to do some of my own work like changing toilets and fixing leaking ceilings, but even if I don't want to do a job personally hopefully I'll have enough knowledge to not let a contractor over charge me, or recommend something I don't need.You'll also meet local contractors, and hopefully investors.They may offer an employee discount too.

Is that based on an actual study or your personal experience?

Most agent wants to sell under my personal name and add my LLC name which is the beneficially of my land trust as a additional insured which do not make sense since the property title under the land trust.  

If you can't keep control of your personal finances, you are highly unlikely to succeed in real estate investing.