Jetboil Sol

Heat exchanger stoves like the Jetboil are self-contained and convenient, but as this excellent Backpacking Light article [paywall warning] documents, they're not very weight efficient. The Jetboil PCS was 15 oz, whereas you can get down below 9 oz with a lightweight canister stove and cooking pot of comparable volume . Heat exchanger stoves are more fuel efficient, but you'd need to be traveling a really long time without resupply in order to reach the break-even point.

In the 7+ years since the Jetboil was introduced, however, they've managed to cut quite a bit of weight. The recently introduced Jetboil Sol Ti is nominally 9.5 oz, though some of this improvement is from a smaller pot and much of the rest is obtained by excluding stuff you don't really need, like the measuring cup/cover. (Redwood Outdoor has a really nice video review of this unit.) You can still do better with the lightweight stove/pot, but its advantage is shrinking, especially in light of the Jetboil's speed.