I demoed skis in 2011-12 season with the intent of finding my one quiver for both in-bounds and back country. The Coomback was the last I tried; and purchased in spring of 2012. I skied more than 30+ days on them over 2012-13 season.
There are better floating powder skis for deep, deep days. Better carvers for the groomers or ice. And skis that have more pop and play. But as an all around, get it done, solidly built do everything on-off piste, mountaineering, free-ride, get me through the crud - the Coomback is a fine quiver of one. It craves solid long lines in the deep and holds hard pack well. If you're a poppy powder skier, look elsewhere. (I demo'd the BD Justice mentioned below - compared to the Commback the Justice was a chatterfest on groomers - no comparison).
My Coomback is teamed with a Marker Baron and a Dynafit Titan boot which makes for a heavy tour but solid down hill.
At 6'3", 185', I chose the 181 which takes some more effort for me to turn in the trees or in tight spots (and on long days sometimes wish I'd have gone a shorter). But if you like hard charging Big Mountain lines - Coombacks will Bomb 'em.