Honest and dependable.
Mack is honest and knows his stuff. Thankfully I can do the majority of maintenance on my Benz myself. However for things that were not safe to do at home, or I was unable to do, I brought to him. One of the most frustrating things about owning a Benz is finding a tech that won't charge you an arm and a leg. Even some of the basic tasks (changing a U joint for instance) are ridiculously overpriced in most "import" garages. I believe Mack's prices are more than fair and I've never had an issue with the work. Once he addressed what needed to be fixed, that was it.
He also works on all kinds of cars as well as Mercedes. He did my Camry's timing belt and water pump when it was time too.