Haven't used it yet, but I bought a case of it yesterday at a Mazda dealership. Looking forward to my first oil change in the new '6 : )
Interesting trying to find this stuff... the Mazda dealership in town had never heard of it - the parts guy thought it was the same as the stuff he had on the shelf. Um no, mr parts department guy, part number 0000-G5-0W20-MQ is NOT the same as part number 0000-G5-0W20-QT, you of all people should know this.
So I contacted 3 other Mazda dealerships in the area. One in particular stocks it but was sold out at the time, but parts guy told me he'd notify me when they got their next shipment in... what do you know, he actually did. So if anyone in the Milwaukee area is looking for the stuff, PM me and I can tell you where to find it ; )