Apologies for Diet Pepsi

Dave did 20 Questions this morning and the thing he had in mind was Diet Pepsi. I've been noticing Diet Pepsi is replacing Diet Coke in so many places I go -- United Airlines, several fast food restaurants, many high-end restaurants -- but invariablly the person serving it makes a sheepish expression and says apologetically, "Is Diet Pepsi okay?" as if they are offering you formaldehyde on the rocks.

So is Pepsi winning the Cola Wars? I think they may be 7/8 of the way there, but they are also tarnishing their brand in the process. Do you really want to establish Diet Pepsi as the unenthusiastic substitute for Diet Coke which people begrudingly accept since they have no other choice? Maybe Diet Pepsi is HELPING build Diet Coke's brand as the better choice?