"The refresh has silver accents and that definitely adds to its appearance IMO. Also, it looks like the 'hood' of the refresh is more charcoal colored. (Maybe that's just the pictures?)"
It's my understanding that the Z70va is an updated M6bne, no? I have the WXGA M6 and have had about 15 months of nearly trouble free usage. I agree with the expectations of nearly flex-free chassis, solid keyboard, and understatedly elegant business looks.
The charcoal coloring is paint over the carbon reinforced plastic. It's a bit soft, and if you have acidic sweat, you may wear it a bit thin in places. Not a big deal, as it still appears dark and fairly uniform. The silver trim is also painted, so it suffers from the same wear issues. Certainly not a deal breaker, though.
I must say that I have been very impressed with the build quality as well as the qualiy of the ASUS software. It does what it's supposed to do, does not load you up with a ton of extra junk, and is very reliable. I am an architect/urban designer/photographer and do a lot of travel for work. This laptop has been on 3 continents so far and half a dozen countries, crunching big 3D renderings and huge Photoshop files for 12-14 hours a day sometimes (when The Sheik wants it now, he wants it now!), virtually without a hitch. You can see from my signature that my spec is at the high end of normal, which means to me that this machine is a true thin and light workstation.
The Z70VA sounds like my machine with a higher res screen, double the VRAM, a faster frontside bus, and better wireless connectivity. What's not to be happy with that? I highly recommend the Z70VA (assuming it's the M6 refresh) based on my personal experience with the previous generation and high respect for ASUS products in general.