I got a print back that was much too dark, and when I emailed Mpix about it, customer support told me they didn't have profiles available at this time but offered to send me a monitor calibration kit. I got that, but since I calibrate with an EyeOne, I don't really want to muck around with a different calibration.
Come to think of it, I had said I was using Lightroom, and the response was "no profiles for Lightroom", so maybe they *do* offer profiles and I just asked wrong?
So the big question now is, do they offer profiles, and if so, how do I get them?