I've had the 79220N (BBBlack ETA) since it came out, and love it, but I would have got the 58 if that had been an option then because I like the smaller case sizes. To scratch that itch, I've since added a BB36 and absolutely love it. If I had to choose just one, it would be a very difficult choice indeed, but I wouldn't give up either for the 58 - the 36 because it works for any occasion and oozes class, the BBB because of the rarity (and the case size has totally grown on me as it is not far off the 58). The 58 is everywhere, the 36 is a bit more unusual, that's the one I'd get out of these two.
I need to get some moisturiser on my arm...
79220N