Well, so far I'm afraid I'm not having a great time (yet).
With limited time to spend, I decided to see if I could get things set up well enough for me to tune around on 20m and hopefully hear a bit of SSB or PSK.
I connected the DC power, the antenna (to Ant1), the ethernet (to my LAN switch) and plugged in some headphones. Then I turned on the 6700 and launched SmartSDR on my computer - admittedly Win8 running in a VM under Parallels 8 on my Macbook Pro retina.
The radio went through its boot cycle and after a few light relay clicks it displayed "Flex-6700" on the front panel. The light that was blinking green during boot, immediately went to solid amber when the radio had completed booting.
On the computer, the 6700 was discovered on the network, but sadly attempting to connect to it resulted in a short pause and then the UI appearing, but with no signal apparent and no controls actually working as such. You can click around, the band selectors appear to jump frequencies, you can scroll, move volume controls etc, but really nothing actually works. Also, there's absolutely no sound from headphones plugged into the front panel - not even a little noise.
Apart from the evidence that the network was working well enough to get the radio discoverable by SmartSDR, I watched my LAN DHCP service provide an IP address to the radio and there's an amount of activity in the ethernet lights on the back of the 6700.
This could certainly be some oddity having to do with either Windows 8, or the Parallels VM. I shall have to borrow a PC tomorrow and try with that so I can rule out the Mac as a factor. Nevertheless, the Mac runs an awful lot of software perfectly in Windows in Parallels and there's absolutely no sign of network issues in general. There are also plenty of reports of SmartSDR running just fine for people on Macs under Parallels and Fusion, and my Mac Pro Retina has plenty of oomph.
Obviously, I'm hoping for this to be something niggly. There's no outward sign that the hardware could be damaged or faulty (from physical evidence and the apparent success of power-up self-tests).
Anyway, I shall hopefully learn more tomorrow.