I am not sure if I read it correctly, but I see that those who go for PEN are mostly Olympus fan, and will accept PEN more because it is an Olympus, and have no problem with its auto focus speed, have a lower resolution screen, and does not have flash built in. They are mostly already experienced owner of dslr, and are very knowledgeable about dslr photography, and thus can work out how to overcome those issues and take very good picts with the PEN.
For those who bought GF1 (including me), they bought it for the flexibility (interchangeable lens for various ocassions) plus portability (almost pocketable, comes with flash, and can leave home without any accessories), and still able to take very good picts compared to a normal PnS (in the hand of a good photograher). They include first time buyer (me) as well as experience dslr photographers too.
So I think both GF1 and PEN share the same advantages of the m4/3 format, and would in the end comes down to your own preferences.