Overall, I'm pretty neutral about Mechanic One. They were upfront about what they were charging me for each service and sought my permission before doing each. They had my car overnight and I got it back when they promised (within 24 hours).
What I don't really appreciate is how extremely expensive their services are and how they kept calling me, trying to get me to agree to more. Both men I dealt with were polite, but I was pretty frustrated that when I opted for financing, the gentleman who was trying to help me had no clue what to do and knew very little about the actual options this shop offered.
As a side note, since taking my car to them, my alignment has been WOEFULLY off, so now I need to invest in having it properly realigned. Though they did help my transmission a great deal.