- Familiarity: I've used it several times
After the first month of skiing the Alien RS, paired with the Black Crows Evo 85mm underfoot ski and ATK Evo binding (now re-branded and sold by Black Diamond), I am very impressed. I've skied them 2 days inbounds, 8-days backcountry. One day of the backcountry skiing included a little 5th class climbing. Three days included extensive crampon use (CAMP Race with Dyneema strap).
Other boots I currently use regularly: Alien 1.0, Dynafit TLT-5 Performance, Dynafit TLT-6 Performance. I wear mondo 30 in all.
The Alien RS fits me very well and feels just a little longer than my same sized Alien 1.0. (Had to punch one toe in Alien 1.0.) I have punched all other of my boots, except the TLT-6, in the lateral metatarsal area. I will not need to punch the Alien RS. I have not thermofit the liners and see no need to do so. The first day I wore them, I felt a hot spot mid-lateral foot where there's a seam in the liner--went away after the first day of resort skiing.
Performance of the Alien RS is superb, on par with my experience with Dynafit TLT series, but with less mass. It walks well, holds well on rock, kicks steps when setting a booter, and of course skis well. Range of motion for skinning and walking is smooth and as unhindered as the Alien 1.0.
Comfort is most similar to my TLT-5, which has an aftermarket Intuition liner with similar thickness to the stock Performance TLT-5 liner, but with a slightly more progressive flex. The Alien RS BOA system is more comfortable and secure than in the 1.0. I've only been skiing in pleasant Spring weather, so no evaluations of their warmth. I expect them to be at least as warm as the TLT-5, which has a reputation of being cold, but is not my experience.
Design comments...the cuff system is a huge improvement over the Alien 1.0. I expect the cord system in the cuff to be more durable than the cuff fastener in the 1.0. The BOA system cable is not obviously accessible and appears that it will be much more difficult to replace than the BOA on the 1.0. Donning CAMP Race crampons feels more secure in the heal area on the RS compared to the 1.0...no issues keeping the crampons on.
I'm really surprised by the other review "Broke Immediately--No Warranty". I'd like to see Backcountry take care of the warranty and respond with their perspective to the review.