An Alphamid-style will be my choice when I get around to making or buying a new 3+ or 4 season shelter. I use a bivy and poncho-tarp in 3 season conditions, but want better protection for when snow is likely.
From what I can tell, Alphamid advantages are easy setup, few stakes, few or no guylines, only one pole, good wind shedding, vertical door, etc. I understand that Ryan Jordan has used one quite a bit lately, so hopefully we'll see more articles on this style shelter soon. Some info is available from the recent Arctic Expedition.
Steeper-walled Alphamids supposedly perform better for snow load and condensation (drips run down walls instead of dropping on you). However, if I built one right now, it would be trekking pole height with flatter walls, for which I would compensate by not letting too much snow accumulate and using my bivy inside for drips.
I think we'll hear more about the Alphamid-style shelter in the near future. At least I hope so.