Obviously the EX2F is more versatile than the GRD because it has a zoom lens. It is a bit bigger though; I think the GRD will fit in most pockets except maybe jeans pockets, whereas the EX2F will be coat pocketable at best (I sometimes carry my EX1 in the side pocket of my walking pants, but then I have to wiggle it in/out, and it can't accommodate a case).
My overall impression of the EX1 is very positive. It's not the fastest camera in terms of operation (autofocus is slightly behind LX5, write times can be painfully slow, particularly in raw+jpeg, although I believe Samsung have finally moved to compressing their raw files which should help a lot). Taking off the lens cap (and if you carry it with the amoled display folded closed, opening the display) does mean it's a good bit slower to take out and fire off a shot than the GRD.
However, the EX1's lens is truly excellent; wide (which I love), with a useful zoom range, and fast. Ofcourse the EX2F has an even faster lens, particularly at wide angle, and an ND filter which should help in keeping the aperture wide open even in daylight, giving you some DOF control. The rotating screen is one of the standout features: good visibility, and the added compositional options it gives you are priceless. I don't understand why rotating screens aren't much more common, given that there're very few camera features that give you so many more options regarding the most important part of photography (composition) as a rotating screen.
The manual controls are GREAT: you have direct dials for shutter speed and aperture, if you click the shutter speed dial it turns into an exposure compensation dial, and if you press the up button on the rear dial you're changing the ISO setting. All with one hand, which I prefer over having to use both hands to change settings. You can set the drive mode dial to be a raw/jpeg dial as well, at least with the EX1. Ricoh's UI looks great too, by the way. The camera is also rock solid
As I said, the lens is sharp, and the raw files allow you to get very sharp images indeed. I don't know about the EX2F but one major downside about the EX1's jpegs is that you can't dial down noise reduction. Overall jpeg quality is quite nice though. EX1's sensor is okay, I usually go no higher than 400, although if the circumstances aren't too bad 800 can still give good results if you use raw and work it in Lightroom. EX2F has a new CMOS sensor that we can't really judge yet.