I don't know much about the Samsung (other than what I heard about the previous model), but why are you limiting yourself to those two models? Have you checked out the Panasonic LX7? Olympus XZ2? Sony RX100? Fuji X10 or XF1? The LX7 is fairly similar to the Samsung and has great manual controls. And except for the lens range, the XZ2 is also. And the Fujis and the Sony have better/best image quality relative to any of the others, if that matters to you. If you have your heart set on those two, I'm sure someone can weigh in on the Samsung, but there are a number of fine cameras in this category that may be worth your consideration unless you have a specific reason not to consider them...
-Ray
Thanks for your response Ray! Well, as I'm sure you can tell I'm really trying to figure out which compact is right for me. Truthfully, I hadn't even heard of the GRD until a few weeks ago and I'm pretty amazed at what I've read about it. Fact is, I prefer to shoot (or convert) to B&W and on occasion do color. If I do color, I don't like the over-saturated approaching neon look. I want full manual control without having to menu-dive. When I first saw the GRD IV it was like looking at my K-5 embodied in a compact (a bit of hyperbole, but you know what I'm getting at). Then I explored the high-end compact market, which I'd never done before, and was amazing at what's out there. So, that made what I thought was an easy decision, namely to just get the GRD IV, a bit more complicated. I know that I want excellent, fast glass. In a dslr, I'd usually stay away from zooms because they are often slow at telephoto and not too fast wide. So, I like primes for speed and quality that would cost a fortune in a zoom. But I had various focal length primes for my K-5 so I wasn't limited except in terms of lugging all of the gear around, which is one of the several reasons that I sold my dslr.
As far a the choices other than the GRD IV:
LX7: The function ring around the lens doesn't seem like a great concept to me. Lens seems great. Manual controls seem OK.
XZ-2: Again, the function ring doesn't really appeal to me. I don't want a touch screen with all the touch screen functionality. Lens seems great.
XF-1: Seems like a lack of manual control as far as I can tell, maybe I'm wrong. Lens is rather slow at telephoto.
X-10: Seems like a very good option. Has OVF. Lens is a hair slower than GRD IV and quite a bit slower than Samsung, etc. Don't know too much about it except that everyone's x-10 seems to be in the shop getting or new sensor or they are seeing "orbs". Don't know if that's been resolved by Fuji.
Samsung: Seems like a great lens. Good UI when in manual mode and, from what I read, very good manual controls.
Sony: I'm not ready to jump in there yet. "RX200" perhaps.
GRD IV: Great controls. Can use OVF. Great UI. Only issue, which may be a non-issue in practice, is the fixed focal length. But for that, I'd have purchased it already. As I said, it's not that I prefer a zoom, it's that I'm concerned about being limited to 1 prime.