In reply to The Ice Doctor:
> Mountaineering use only. High altitude, in all weathers and potentially minus temperature conditions.
Are you talkin' about real high altitude or the Alps?
For real altitude, jetboils/reactors are the thing almost everyone is using. Think of Everest, Chogori and so on.
For expeditions (and basecamps or siege style stuff). Liquid fuel stoves (like Optimus Nova something, MSR XKG II or Primus Multi/Optifuels) are mainly used.
Liquid fuel stuff is also used when low and cold (sub 5000). So winter Alps and Scandiland when bivouacking and going slow & heavy. For fast & light, Jetboils (or similar) seem to be the choice.
I have a Jetboil version from Primus... and also Primus Multifuel (old version of Omni, not as easy to set to simmer)... Plus MSR Pocket Rocket.
Pocket Rocket gets very rarely used, the Jetboil-alike is used pretty much always on alpine trips and when I have to lug the stove in the sack. Multifuel is used with gas-cartridges on summer car-camping trips and with liquid fuel on winter dealios (when no warm shelter is available).