The MBPr screen is definitely not a viable substitute for an antiglare screen, IMO. To me, the MBPr is just as glossy/glassy/reflective/annoying as all the other mirrors that Apple uses for screens. The lack of an antiglare screen option is one of the reasons I won't buy an iMac or ACD or MBPr. If they stop offering antiglare completely, I'll be forced to find an antiglare film, because the glossy screen is unusable for me.
I haven't seen an anti-glare film that really works though have you?