I would choose Guerlain because of all the wonderful fragrances they have created in the past, many of which have been my favorites, but after seeing (smelling) what they have done with their heritage, I'm going for Chanel.
I think Chanel has done a better job reformulating their older fragrances and I feel the materials they use are superior.
I will never forgive Guerlain for what they have done to L'Heure Bleue extrait.