We hardly ever meet our tenants in person.

Also, while I've read some horror stories about assessed value increases, our personal portfolio came out relatively unscathed during this recent batch of tax bills.

If rent is not paid we follow up personally.

Though a cost seg study doesn't increase your chance of audit, if you happen to go to audit it would be very tough to defend as a lay person. 

I plan to hand write the letter to keep it personable and local.

I personally have invested in a couple syndications in the last 3 years and none have been completed yet.

On a separate note, if my personal home and all my business is in the state of Michigan at this point, would there be any benefit to designing the business as a series outline or simply a parent/child LLC set up where the parent LLC would be created in a more tax advantaged state such as TX, WY, NV etc?

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

One of the complexes was over 1,000 units, I even went to see it in person, very nice, well kept, and great condition and great location.

This tenant is a great example of why they should never have a personal cell phone.