Canister vs. White Gas

Fuel Availability

Canister: Fittings are well standardized to three types — Camping Gaz on its own, Coleman/MSR/Snow Peak/Primus with the same fittings, and Coleman Max on its own. This means there's a good chance of finding a compatible canister. MSR SuperFly stove fits Gaz as well as its own and Coleman, etc.

White Gas: Good availability in North America, many will burn unleaded auto fuel too. Multifuel models widen the choice to include Gasolina Blanca, Kerosene, jet fuel, diesel etc. This means you can find something to cook with almost anywhere in the world.

Running Cost

Canister: Running costs are very high compared to white gas. This becomes a significant factor on long trips or if you use stoves a lot.

White Gas: Very cheap to run — a gallon of white gas can be bought for little more than the price of one 8-oz canister.

Reliability

Canister: Good — few moving or maintainable parts, but when burner is separated from the canister, dirt can get into places where it can cause trouble.

White Gas: Good if used and maintained in accordance with instructions. More scope for dirt to enter when filling, or if halves of stove are disconnected. Risk of contaminated or low-grade fuel clogging jets. However, if that's the only fuel you can get, you'd probably not find any canister fuel at all!