I'll be sitting this one out. It's appears to be a fine phone, but I'm not after something of this size. I think Google and LG hit a genuine sweet spot for me with the dimensions, materials and weight of the N5. I could and would tolerate a few mm here or there, but a 'phablet' is just one step too far (although I do admit to enjoying using my OH's Lumia 1520 when at home).
I'll stick with my N5 for another cycle, I think. I have no doubts that it will continue to be a very strong performer all the way up until the next major Nexus (or equivalent) announcement.
While I'm a little sad I'll have to forgo what has been an annual tradition of refreshing my Nexus phone, since the GNex, I am on the other hand very excited about the forthcoming Nexus 9; every cloud has a silver lining and all that...
Speaking of silver (sorry), incidentally, the N6 looks very much like the kind of device we would have expected to see under the rumoured Silver branding; highest specs, pure Android, strong carrier support, etc. This looks suspiciously like confirmation of the aborted (or postponed) Silver programme. It especially seems that way to me when you look at the design language used by the N9. It shares many design cues with the 2013 N7 and even more with the N5, i.e. a device that was always intended to be a Nexus. The N6 (in terms of design) is quite literally just an inflated Moto X with a big 'Nexus' stamp on the back.
I may be barking up the wrong tree with this, but that's how it seems to me.