In reply to AnnieKanani:
Even for us blokes there aren't too many options for a super warm proper belay jacket.
ME Citadel is definitely top of the list but (if last year is anything to go by) surprisingly difficult to find in stock anywhere to try on.
After that the better options are probably the RAB Photon X probably followed by the Patagonia DAS Parka. I believe RAB may do a female version
Pretty much everything else like the ME Fitzroy and the Decathlon/Simond, Alpkit and Montane equivalents aren't quite as warm.
I currently have a Photon X as I got one off Sportpursuit far cheaper than I could find a Citadel. It's a lot warmer (and bulkier) than the RAB Generator Alpine that it replaced for hard routes.
One obvious question is what sort of climbing/mountaineering you intend to be doing. I used my RAB Generator quite happily for years and when belaying for half an hour on an ice or mountaineering route I'm fairly sure that the Nebula Pro (which seems fairly similar) would probably be good enough for lots of people. However, if you're going to be belaying someone on hard mixed climbs for two-three hours then you'll almost certainly find it lacking, although that might well be the case regardless of what jacket you have!
Finally, your jacket isn't the only issue to consider - thermals, mid-layers, buffs/hats/balaclavas and belay mitts will all make a contribution to how much heat loss you suffer when stationary.
Post edited at 22:56