Well, now I know why the NX300 was such a great price: it's missing box flash and battery. And registration papers, and manual.. and Lightroom 4 come to think of it! That was pretty much stated on the listing but I failed to do my due diligence. In this case I'm OK as a battery (my 'spare') arrives tomorrow and I can contemplate the flash options for a bit. I've ordered a spare spare battery now. I will contact them about how to register and get a copy of LR4 software, and on to Samsung after that.
Re. comparisons - I've boxed up the Pentax K-5 IIs so only the Q can take photos, making it difficult to compare the NX300 to another camera. On the other hand it's smaller than my 5"-screen cell phone in two of three dimensions, so that's saying something. The Q is definitely smaller in every way, but given its 1/2.5" sensor the comparison (0.4" against a 1.15" using that math) gets a bit silly. Silly data is still data though, so there it is.
Well OK, it's pretty bad but the phone in fact can take an image of the two cameras together. I warned you!