I'm thorughly satisfied with the Cobb tune I installed last week. I'm sure most of the tunes will be similar in performance, but I wanted to touch on the cust service aspect.
I tried installing my Cobb tune last Thursday night. During the install attempt, I found that my vehicle ROM was not included in the latest Cobb AP firmware. It was likely updated at the dealer recently, so not a surprise. Therefore, I couldn't install the tune. I went ahead and downloaded my ECU data, then emailed it to Cobb later that evening. I received a personal email back from "turtle" at Cobb that evening, even though it was considerably after hours. She (turtle) expedited the addition of my ROM into the beta firmware first thing Friday morning and I was up and running well before NOON. Not only were they very very quick to acknowledge my initial email for assistance, but they were very very expedient in addressing/resolving my issue.
Huge props to Cobb, the lady name "turtle" at Cobb, and her engineering team.