get a feel of the cameras is the best way to help u decide on it.
go to a shop and try them.
bring along your SD card.
GR-D & GX series are totally different kind of camera.
one is a prime, one is a zoom.
could u live with a fixed focal length?
or do u need a zoom to fulfill your needs?
GR-D is not everyone's cup of tea.
normally, people who get GR-D are people who already know what they wants.
don't get it because someone say its good.
if u get it because of that, whats so good about it?
only yourself will know why u feel its good.
i see, and know quite a few people who gotten themselves a GR-D happily, and sold it in matter of days.
so, try it first, think n know what u want.
take this example,
"a man walks into a showroom and ask, how much is this watch?"
salesman reply, "if you ask the price, u can't afford it."
its the same as, if you're asking how is the GR-D being compared to the GX series, most likely, u don't need & won't like the GR-D.
btw, i'm a GR-D II user. used to own a GX100 also.
just my little comments.