Viewfinder
I have a GX1 with the optional VF, I rarely use the VF... no real requirement for it so far although I imagine this will change slightly now the sun has come out. I moved from a DSLR to the GX1 to save weight and bulk, its made a hell of a difference, I can now take my camera, 4 lenses and filters etc out with me in a v small bag whereas before for the same kit I was carrying a largeish rucksack, and have better IQ (imho) than I did with the Canon.
To be fair if I had seen this cam before I bought the GX1 I think I would have given it serious consideration.