I was shopping around for OEM brakes and found a dozen online parts vendors, but in terms of positive reviews and good price ended up settling on Husker bmw at bmwdirectparts.com
They followed up on my order, Vic @ Husker pointed out that I had forgotten one small part, and shipped very quickly. I placed the order on a Sunday and got all my parts on friday!
PS: Some of the online vendors had a default $100 shipping charge as soon as I added rotors! My total shipping bill from bmwdirectparts was about $50 for all 4 corners.