I like the Jetboil stove. And I can see the appeal of using one if:
1. One already owns one and does not have a
marine propane stove on a boat
2. One is going for short trips on boat (e.g. overnight) and does minimum cooking.
3. One wants just hot water for hot drinks or instant
meals (no complex cooking or simmering required). For a
racer this is possibly a good fit. For a
single hander who likes to eat only "boil in a bag" type
food, this is possibly a good fit.
But, there are other reasons why I do not see them as an "ideal" solution for a cruiser on a
small boat:
1. It is a propane/butane type
fuel and poses some risk inherent with that type of gas, because the gas canister is attached to the stove and in the
cabin.
2. The
fuel canisters take up space and should be recycled. A long
cruise could use several or many of the canisters.
3. The fuel canisters may be difficult to find while cruising
remote areas or abroad. They are specialty items.
4. The average Jetboil is great at fast high temperature heat, and very quick to boil water, but very difficult (on average) to simmer (low heat) and hence difficult to cook average foods (not just boiling water).
I think if a
small boat does not have a "propane" stove (already in the boat with safe links/lines to the properly vented gas bottle), an alcohol stove of some type (but not pressurized alcohol) would be my choice.
At sea level, alcohol stoves can also boil water effectively, if a bit slower than
propane, and can be used to cook and simmer more foods without the risk of a hot spot burning the
food (a very common problem with high temp Jetboil type camping stoves that are difficult to "simmer" with a low flame).
That said, there are some risks with any kind of stove, including an alcohol stove. Alcohol is relatively safe, but it is important to make sure it does not spill while in use, as the flames are difficult to see and one can easily get burned or the flames may spread to other flammable items (potential disaster on a boat). For this reason typical low cost "homemade" (open
aluminum cans) alcohol stoves (popular with backpackers) may not be safe on a moving boat, and should be secured.
Since I like to cook and I like to eat more variety than just "freeze dried"
meals and oatmeal and hot drinks that only require hot water to fix, I would look beyond a Jetboil if I were planning on doing some cruising for more than a weekend.
NOTE: My comments above apply equally to the MSR stove and similar competitor stoves similar to the Jetboil.