In reply to nicjbuk:
I've one I use for mountaineering type outings in winter and MR stuff. Good as it's light and compact. Not one to hang in all day, though I did hang for c.10mins in it and was only minorly uncomfortable. Since you'll likely have a couple of layers underneath it I'd say it'd be fine for most things alpine, unless your looking at hard alpine rock routes where you're expecting to hang / fall.
I don't tend to carry much gear for alpine / mountaineering type terrain so limited gear loops were fine and nappy style is good as not a faf getting it on over crampons.
The waist buckle is fiddly to release though! That said, not a bad thing that a harness you'll be wearing all day is fiddly to take off / pull the waist strap back through!
All that is assuming you're talking about BD couloir rather than DMM super couloir.....
Cheers,
Stuart