Lajhanata wrote a review of MSR Reactor Stove on December 27, 2007
This thing might be cool in fair weather, but it's not a mountaineers tool.
THE CONS: The hype about the pressure regulator making the fuel run more efficiently is total bull. If the canister is sitting in snow, the stove quickly weakens to a whimpy simmer which make snow melt times pathetic. When they say not to use it in a tent, they aren't kidding either, mine belches a 24 inch fireball every time I light it. Don't set the the pot down in the snow or the integrated heat exchanger will be packed with snow. Don't boil over either, the exchanger funnels water (or in my case hot coco) down into the heating element. No auto igniter on these puppies, which might be nice when you don't have a lighter handy. Finally, the actual stove assembly can't be set in the snow either. Getting snow in the element or in the IsoPro fitting makes the stove inoperable. Oh, and Iso is expensive!
THE PROS: In warm weather, the stove rages! Mine boils a quart of water in under a minute. The pot is nice and big too. I can fit two Tasty-Bites in mine at a hard boil. The little pac-towl is handy, and the rubber knob on the lid can handle a fair bit of pack crushing.
Overall the Reactor is useful for fair weather camping, but when the snow flies, leave it at home.