I have about 15 days on my Ultracraft 156 including 7 days at touring out of the Hilda Hut in the Slekirks BC during a fantastic storm cycle. I was nervous about the short size considering that my weight (185 without backpack) is pushing the edge of the suggest weight for that board. But I ride a size 9 boot which is smaller than suggested for the longer 160 size and I was worried about the wider edge-to-edge width of that longer board. I do think my 156 board rides a tad slower than my more traditional shaped split (a 165 Prior BC) but the UC is WAY more manueverable though trees in deep powder. In order for my old board to float to the point where it was easy to turn I had to be riding faster than I wanted to in tight treed runouts. The Ultracraft doesn't have that issue at all.
My fears about the UC not being stable on high speed, longer radius turns were put to bed once I used it in that kind of terrain. I did notice my turns tend to be a bit more rounded and short radius compared to my other board but the ride never feels wobbly or unstabe. And shoot, I'm getting older (48) and am enjoying working the terrain differently than I did in my straightlining days.
If Jones offered this board in a 160 length with the same waist width as the 156 it would probably be perfect for me but I have no regrets on the 156. WIth my full BC kit I'm weighing in at 208 lbs.
The downsides I've noticed are more related to the Karakoram hardware. Between the camlock tip/tail clips and the mechanized yin-yang clips, there's three different sizes of allen wrenches needed to keep things tight. And all of that stuff has needed to be tighted repeatedly in the field. In fact, the tip clip (which threads directly into the board) would always tigthen or loosen itself while working the clip. I installed a longer bolt with nyloc nut to fix that but don't think that was too cool. The nut now messes with my climbing skin install as it interferes with the tip wire on my skin. Carrying three different allen wrenches in my repair kit is an unnecesary hassle. Maybe team up with Spark RnD and agree on one size of bolt head to use for EVERYTHING on the board.
I also wish it was available with a white topsheet. Maybe it's just superstition but I think smooth white topsheets limit snow build up on the top of the board which keeps things less heavy.
All in all I love it and have recommended it to my friends.