This might be a bit late after the initial posting, but I just got my JetBoil and I really like it.

The time it takes to boil water is insanely short. Granted it only works for water and it'll undo/redo some people's notion of cooking out in the woods.

Retail is $75 and it's a wee bit on the expensive side if you do a comparision of a) how much water per fuel it can boil (approx. 11.5 liters) and b) how verstile it is (not very, but if you look at Jetboil's website they do have alternative recipes for it).

On the flip side you've got those prepared dehydrated foods that require hot/boiling water to rehydrate/cook. This would be an excellent use of Jetboil.

As for the question regarding fuel, it can run on non-Jetboil fuel but the performace is about equal or nearly so. At least with Prima fuel.

While it's not as light nor as verstile as say a MSR whisperlite, it's great if you go for a easily stored cooking device. As for mentioned, the fuel and the burner can go inside the cup.

Cheers!

I have taken a Jetboil on a couple of lightweight hiking/camping trips this year, and it is amazing how fast it works with liquids. It's great for making a hot drink to warm your core when you're hiking and want to take a quick but effective break. It's also great for making one of many different adaptations of the classic hiking food, Ramen noodles. For breakfast, oatmeal is my basic staple, and it gets hot water ready in a flash. If you're using dehydrated meals from Mountain House, that just need boiling water to make them edible, this will do the trick.

I think the best thing is that it's a compact unit that you can take along, with nothing else but a spoon, and have all the cooking kit you'll need for a lot of situations. In the past, I was always trying to figure out if I need the pot, pan, cup, plate, etc? A full mess kit, even titanium, is bulky, and then you still need a stove. This thing packs into itself, fuel, heater, and cook/drink cup, and is about the size of a 1 liter Nalgeen bottle when packed.

What I've found is that it's compact and light enough that I put it in my summit bag for day hikes. I have had plenty of times when I was on a day trip that got colder than expected. A hot lunch, or even just some cocoa, at the right time, can really lift your spirits and get you through a miserable time.

I typically have the unit in the daypack in the back of my car, so it's also part of my BOB.

Downside, from my experience, is trying to heat anything that isn't very fluid. It can burn things quickly if they aren't fairly liquid. You wouldn't be happy trying to warm up your thick Dinty Moore stew in there, because you'll be stirring it constantly. (And I love that stuff.) That's not a big problem for hikers, because usually we're taking lightweight stuff that just needs hot water to reconstitute it, like noodles, pasta, granola, oatmeal, etc.

Lastly, someone earlier asked about where to get the Jetboil fuel. Our local EMS (Eastern Mountain Sports) stocks them, along with REI. In addition, some places will ship them, using ground only, for example, Mountain Gear sells a 6 pack of them:
http://www.mgear.com/pages/product/product.asp/level1_id/0/level2_id/0/level3_id/0/item/103705

I still like my liquid multi-fuel stoves. I can run it on White gas, kerosene, jet fuel, unleaded car fuel, and #1 diesel. It sits nice an stable. I can use a pot or just a steel cup on it. The jetboil sounds neat, but I wouldn't replace my stove with it just yet.

I'm not too concerned with getting a hot cup of coffee or cooking ramen, and MREs already come with heaters for the entrees...

However, I would be interested in hearing about jetboils value for boiling questionable water for drinking, and maybe melting snow for drinking. I haven't really considered a stove, and I'm not sure I need one, although I have been looking at those small folding stoves that uses solid fuel

I think I'd go with the classic soda can stove.