Very easy process - seamless handoff from Thumbtack to Assemble All Install. Ivan texted me 20 minutes before he arrived, and was within the 3 hour window we scheduled. He understood my goals, and recommended a few options. When I was pushing for a second outlet to hide the cables, he proposed an alternative that was about $150 less. He's definitely looking out for the customer, and not trying to earn a quick buck. The final mount looks great, hides all the cables, and is sturdy.
Special note about a clever solution: I had a particular need to both center the TV and not cover a wall switch to my patio. Ivan figured out a clever way to do this while maintaining a flushmount - he made the mount slidable. So, the TV is centered most of the time and looks great. When I have guests outside at night, I can slide the TV to easily access the switch.