I recently (yesterday) had a chance to demo the Nano at Smugglers' Notch Vermont during the Backcountry Demo days. Conditions were very mixed - with some mashed potatoe style powder, breakable crust, hard pack and bumps. I was using a pair of BD boots w/ a tech binding. I'm 5 10 and 155 pounds. Pretty good skier.
My standard setup is a pair of older Dynastar Legend Pro's with a Marker Duke binding. My immediate reaction to putting the Nano's on was "holy shit, these are light". Not just a little bit lighter, but light like "did these fall off my feet by mistake light". Freaky light is the only way I can put it.
First run was down some well skied main lines and I found the ski to be pretty scary at speed on hard pack. The lightness let the ski get pushed around a bit by bumps and bits of crud and I had to really control my speed to stay happy.
Next run was down a very steep mixed (some packed, some ice and some mush) chute - narrow enough to require jump and fast turns. Here the skis were both amazing and scary. The ease with which I could snap the ski around from one landing zone to the other was incredible. With some practice I think I could probably make a 4' vertical leap with these things on. Make a jump turn or quick chute kick turn was stupid easy and I found myself just jumping over obstacles that I might have side stepped over normally.
Again - the light weight was so incredibly light that I didn't feel terribly secure when work across the fall line on ice and hard pack, but the maneuverability was pretty amazing.
Last run was through a combination of fresh spring 'powder' (think sierra cement) and some breakable crust. Here the flex pattern and weight really came into play - with the tip riding up and over nicely. Tail seems stiff enough so that I could get out of the backseat pretty easily. Excellent float.
My take away was that these would be ridiculous to have on a nice powder day in the back country - really easy to skin up with and sweet through trees and pow. As an inbounds and out of bounds ski they are just too light to be trust worthy (not to mention I'd hate to break a $1,200 pair of skis skiing shit conditions).
For really steep skiing I'd again want to have a little more substance under foot.