Just wanted to add a few observations regarding the fit of these boots. Enough was said about ski performance and I'm not a ski expert to add much on this subject.
It was an emotion-driven purchase. My beloved LS Syborgs all of a sudden turned into torture device when some kind of bony protrusion grew on my foot and it gotten really painful after only a few hours of touring, especially when in a ski mode. I went to the ski shop to try to do something about, saw Alien RS, put them on and pulled out my cc!
It's been a little tight at the forefoot first few outings but then it went away and now the boots are really comfy! I had the liners molded but frankly I think the fit improved just from usage. Anyway: my feet are old, medium width, pretty wide at the toes but these boots fit great! I probably went with 1/2 to 1 size too large so the fit is not "performance fit" but they ski great for me and very comfortable. No hot spots, no blisters, nothing! Maybe I should try a foot-bed to take up some of the slop but maybe it's like trying to fix what's not broken?
A few other things: crampon fit with my crampons that I assembled for Syborgs from several different parts is awesome! BOA adjustment is fantastic, super easy to tighten and you just pull the knob and it loosens. The gaitors have no zippers to break. Liners seem thicker and way warmer compared to Syborgs. It's really easy to put the boots on which is kind of nice when you are on a multi-day tour! I'm in love with these boots but let me point to a few negatives:
Ski/walk mechanism is way harder to work compared to Syborgs. You need to bend back to reach the lever and it may take a little fiddling. Really no big deal and I'll probably learn to do it quicker with time.
As others pointed out, the cord for tightening gets frayed pretty early and the cord slips through the locking fitting when tightened hard. A knot on a cord would probably solve the slippage problem.
I'll add other negatives if I could think of anything else.