Like Shinobi326, I too was curious to try McD's coffee. Sadly, without a free drink card so I can't comment on any cashiering issues. Anyway, I hit the drive-through, and ordered a large, iced, hazelnut coffee. The coffee was way too sweet for my tastes, and not cheap--apparently I "just don't get it" either.
Their coffee was $1.99, Starbucks runs around $2.30, albeit sans flavorants.
I have a feeling that like the McRib, the McD LT, or any number of failed promotions (although the nice ladies from McDonald's were quick to mention that over the last five years, nothing has been short of success--but upon reflection, I can't remember McDonald's introducing anything new in the last five years) their iced coffee program will be McGone.