Having used both liquid fuel and canister stoves for hundreds of meals, I prefer canisters up to 13,000 feet. With canisters, you don't get quite as many BTUs per ounce. However, when you factor in the spillage and priming factors for liquid, I think it's about equal. (I also think the extra ounce for a built in ignitor is worth it, because you tend to shut the stove off immediately knowing it's easy to relight, and you waste less fuel lighting it.)
I use the freezer bag food method and only "cook" with treated (Aqua Mira) water. I can easily get 16 to 20 person-meals out of one 8oz canister by cooking on low, making sure there's little heat loss up around the sides of the pot. Your mileage may vary. If you're planning on doing lots of real cooking and/or water purification, then liquid may be worth it.
One more canister tip: I agree with the comment about cold temperature reducing the efficiency of the stove. If you're expecting a cold night, keep your canister in the bottom of your sleeping bag, then stick it inside your jacket when you get up, until you're ready to cook.