I also likes the tonality of Kodak BW400CN. You got the clouds very beautiful. I took some family portraits (but they wont be published), and they came out very nice, almost without grain, as your images.
I have found out BW photography differs from color, one must look for shadows, light and texture to get nice BW images.
Forgot to say, BW400CN is desireable if processed at a general C41 lab (my own personal opinion). Ilford XP2 is also a good C41 BW film, but, it demands more to get nice copies from the lab. It might have to do something about the film base, Kodak is more convenient for the small lab at the corner. Anyone else have experience here?