Since I bought my MINI in Aug 2009, it is still under the 3 year maintenance period, so I have gone to MINI of Sterling a bunch of times, and have had good experiences every time.
The only thing I have gone to Mach V for is oil changes midway between the ~16000mi recommendations from my MINI computer and to purchase/install my new wheels.
If anything, I have only good things to say about MoS. They seemed like they went above and beyond any diagnoses required to fix my issues. Even the small stuff, like a slight sound like something was rolling back and forth in the headliner. (Turned out to be a small rock in the headliner rolling back and forth around corners!)
I have never felt like a number, and actually have 2 service advisers that recognize me the second I walk in the door of MoS, and can recall what I was last in for and much more.
I understand the desire to save a bit of money, and I can't say how my maintenance will change after my 3 year period is up, but for now, I love MINI of Sterling.