Builders are able to offer incentives that you can't find on the secondary market. 

What was your top 3 biggest lessons learned?

For me, I am a little hesitant because I would be in a situation where I would be trying to secure traditional lending (which should be very feasible given credit scores & what $$ amount I am pre-approved up to from my banks), meaning that I assume I would be forced into using my first-time homebuyer loan incentives.

@Sunny WuPerhaps offer them an incentive to also help in finding a replacement tenant.

At least for me the biggest complaints are my staff, visitors, etc. parking in front of their house. 

that is more a RV park. the MBH parks down here. we typically own the land, lot, and trailers. there is a reason but long story short, if i just own the lot and they dont pay the fee. i do not have the biggest teeth to push the need for my money. but if i own it all, my experience says it is a better path

You hit on a tough reality.. inheriting tenants who aren’t prepared to pay on time can be one of the biggest curveballs for a landlord.

Why would the company selling that type of product have much of an incentive to keep projections and promises when they have already received most of their benefits?      

The biggest employer shut down about a year ago and 3  hurricanes (2 major) hit directly in the last year.

In working right with the builder I can offer the investors properties that are off market but have incentives that on market properties can't offer.