I used to have a corporate code and everything in Diamond Elite status was given. I also get cashreward bonus too. It had gotten to the point where I bargain for free parking and they offered it. I always go with "Can I substitute my breakfast amenity for parking?". Most of the times they just give you free parking since you are Diamond Elite status.
Nowadays, I use WSJ's code since it comes with AMEX Platinum subscription to The Australian. My corporate code doesn't give me any more discounts 
