I was hesitant to write a review about the Alltime until after spending a significant amount of time on them. I mounted the Alltime on a pair of K2 Sidestash with Salmon STH bindings. I initially got the Alltime, because I wanted a burly setup that I could ski hard in bounds without worrying about durability. I have put in well over 40 days on this setup (approximately 20-25% touring).
The Alltime adds a noticeable amount of weight to the ski and for those weight elitist it is not the AT setup for you. However, I have yet to be dropped (or passed) on the skin track on the way up and these are bomber on the way down with very good power transfer from boot to ski.
If you are afraid that the Alltime will keep you from longer tours, because of the weight... dont be! Although I have not done multiday tours on the Alltime, I have had some long days of touring with long approaches and 6,000ft + of vert with no problems.
The only real concern that I have with the Alltime after skiing it for a season is the impact on the ski flex. I never rode the K2 Sidestash without the Alltimes mounted so I am not sure how different the ski feels, but I believe that it definately stiffens the ski (although the floating heel block helps a ton). Overall, this is a rad setup and has allowed me to ski hard on the best days inbounds and then head out of bounds when the resort is all skied out!