Let me start by saying that I have no prior experience in buying ski boots, nor any experience in AT skiing. However, I have done enough marginal midwestern downhill (almost an oxymoron), some time out in Tahoe, and currently small results where I live currently that get little snow fall all winter. But I am a serious climber and done enough winter mountaineering that I wanted to join some of the AT skiers this winter and started by picking a boot. My first impressions thus are far mostly positive. The boot, while not the easiest to put on compared to the traditional clam shell of an alpine boot, is fairly comfortable. The liner is very beefy and comfortable due to the thick padding. I wore a very thin liner because a normal sock was just too thick-I haven't had the ability to get the liner molded for the few extra milimeters of space to be perfectly comfortable. Nonetheless, after about 8 hours of use, the liner started to break in and be more comfortable over all. The boots are light, and adjusting between walk and ski mode is straight forward and simple. Easily adjustable, and definitely made for downhill. Solid, aggressive feel compared to the average rental boot I suppose. But back to the liner-I wore, literally, a thin business sock in 15 degree weather for 8 hours, and my feet were fine on the slopes. Granted I wasn't in 5 inches of power, but, no issues with being cold (toes mildly discomfort from the break in process). Maybe its the Pebex, but it was impressive to wear something that thin for so long in such cold temps and not be cold. I got the 27's, and it was a toss up between the 27.5's, but since I couldn't try them on ( I live overseas where Blackdiamond cannot be shipped) I followed the BD size chart for 27's. My understanding is that the shell is the same size at 310mm, but the liners are different sizes. Like another reviewer mentioned, a little bit painful in the toes until molded-something I have yet been able to do-but definitely looks like will be a perfect fit once done.