I typically go to Mr. Inspection for the minor oil changes on our vehicles, and then take them to the big-name mechanic for the major services. It isn't that think that Mr. Inspection couldn't do those services, it's just that I like the peace of mind that having two different sets of eyes provides.
Also, Mr. Inspection is a touch cheaper, and since we're typically there several times a year for the regular service and inspections, it can save a bit of coin. They also get us in and out quickly, which is nice.