@rick. The jacket looks good, I'll check it out.
I'm still a little skeptical about the role of designated mid layers for 3 season backpacking. It ads redundancy, complication, and weight to your layering system. The base layer wicks, wind shirt for wind and mobil warmth, shell for the bad weather, and a puffy for stationary/sleep insulation.
Jordan and co make a strong case for this system from the get go: http://www.backpackinglight.com/cgi-bin/backpackinglight/00036.html#.UScaYBy8xyU
and Nilsey, in more tech detail here: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=9378&disable_pagination=1
I'm not sure why polartec high efficiency gives us more reason to carry a mid. Polartec designed it primarily as a base, and the grid fleece wicks best next to skin. I don't think its lightness is a good reason to add it to the pack.
Of course there is a lot of ways to pack (I err on the side of simplicity), and great if it works in your system. Just thought I'd invoke some of that old gospel from our founding fathers. :)
...I'll add, from a purely functional standpoint, a piece that wicks, breaths, insulates, and still has light weather protection, like a vapour rise, boreas or piton makes some sense to me in place of a wind shirt.