Note: I only use this type of stove when camping out of my Land Rovers. When hiking or backpacking, I use small and lightweight stoves like the MSR PocketRocket. When on the motorbike, I use an MSR DragonFly, so I can use the petrol from the bike and utilize a single fuel source.

I’ve been a JetBoil fan since they became available in 2001. When camping, my cooking philosophy is “just get it done’, nothing complex, usually something I’ve pre-made or something out of a packet (I actually like MREs, usually warmed on the manifold). And being English, I mandate several tea-breaks throughout the day, so really I just need a fast and efficient way of boiling water. That covers about 90% of my cooking requirements.

One of my more lightly-used JetBoils failed recently (a JetBoil PCS - Personal Cooking System). The seam attaching the inner part to the outer part (which interfaces with the burner) broke away. I noticed that it was spot welded and the newer JetBoils have an updated design - so they clearly know about this issue. I took it back to REI to get it replaced and while in the stove section I had a longer look at the MSR Reactor, clearly their answer to the very successful JetBoil. It’s of a similar design, slightly wider and the burner interface section has a number of fins which gives the pot a larger surface area and speeds up heating. The burner itself is very large, in terms of area (but quite compact), and is quite quiet in operation.

On a recent camping trip in Utah, I had the opportunity to give the stove a decent field-test. Of course, I boiled water for tea and washing, I boiled milk for porridge (Mornflake Lyle’s Golden Syrup flavour - imported from the UK), which is rather messy, I made soup, warmed some pre-cooked steak and cooked-up some pasta. I noted the following pros and cons.

Pros:

1.  It's extremely fast, I boil a lot of water so this is a huge win for me. Subjectively, it takes around 1/3 less time to boil water versus the JetBoil. This is due to the more powerful burner and larger surface area on the burner interface.
2.  It packs small, and as it's wider than a JetBoil, you can pack a 220g (7.8oz) gas cylinder inside it, whereas the JetBoil can only contain a 110g (3.9oz) cylinder internally (so I always packed an additional large 450g (15.9oz) cylinder).
3.  It comes with a small packing cloth which stops the insides getting scratched when the burner unit is packed inside (yes, you could easily make this yourself, but it's a nice thought to provide one).
4.  The whole unit it the typical good quality you'd expect from MSR.
5.  It's wider than the JetBoil, and that makes it easier to clean.

Cons:

1.  It's more expensive than the JetBoil ($160 vs $100 using REI prices in April 2010).
2.  Simmering is difficult, if not impossible. The burner is so powerful it seems to have only two settings, off and "supernova"!
3.  No <a href="http://en.wikipedia.org/wiki/Piezo_ignition">piezo ignition</a>! It's a pain to use matches or a lighter.
4.  Bigger burner means it goes through gas faster, though as you can pack a larger cylinder internally it may not be an issue.
5.  It is slightly larger than the JetBoil, the diameter is larger but it is shorter.
6.  It has a fold-out handle, the JetBoil is insulated so you can simply pick it up with your bare hands even when hot.
7.  As the diameter of the pot is wider than the JetBoil, it is slightly more difficult to pour into narrow containers.

In summary, I like the Reactor, I doubt anything on the market can boil water as fast. However, until it adds both piezo ignition and a way to simmer I still recommend the JetBoil (especially as the Reactor currently demands a $60 premium).