I got my Jetboil from Jasper at
www.strikeforcesupplies.co.uk, he is a real gent to do business with and it is relatively cheap. You may think it is pricey/big but considering its your cooking pot and stove and fuel etc all in one package I think it is worth it!
Jetboil is damned good for boiling water or putting one boil-in-the-bag (Brit 24hr ration) in, but I recently found that 2x boilies won't really fit very well (I reckon its only worth carrying one between two, as everyone has hexy as a 'just in case'). So I got the little support that you can use for supporting any pan for cooking (comes with some little tripod legs too) and just use my Crusader metal mug on there with 2 boilies in now, like I did with hexy only no black mess. The proper Jetboil pan still comes in useful for boiling water and other stuff, way more efficient than a mess tin or whatever.
The only problem is apparently you can't take gas on RAF planes and then you can't get replacement gas in country, so I'd need something different when its time to go on tour! I know those multi-fuel stoves are meant to be good at altitude and run off anything, but there again its probably simpler to just stick to hexy.