Skied the new full tilt descendant 6 and 8 for two days straight at SIA. For reference, I have a fairly narrow foot and a high instep. My feet have never felt so good after a full day of charging hard. They were brand spankin new, no break in whatsoever and they were still by far the best boot I have ever ridden. Even though they're 'wide' at a 102mm last, my foot felt completely locked down. Due to my high instep, ankle retention has been my biggest problem with every boot I've owned, but the new design full tilt is using completely solves it. Plus 102mm means plenty of room in the toe box, which made them nice and comfy. I will be buying a pair of the 8's for this season. Hope this helps.
P.S. Be weary of "boot fitters." Many shops have a guy that is supposedly a boot fitter that really just tries to sell you a pair of boots, slap some footbeds in, and get you out the door. So make sure you go to a real specialist and emphasize that you want the best boot for your specific foot.
I got the descendant 4's. I haven't ridden them yet but from wearing them and walking around they are already super comfortable. But yea go to a good boot fitter. go to a few different shops to start and see who seems to care the most then choose the place. Like said above some places just want your money