Of the two stoves in question the Jet Boil (JB) is my choice' they are fast and efficient. My preference is the MSR Pocket Rocket because of weight, speed, and versatility. Last fall on our moose hunt in Alaska I took the MSR and my partner took the JB, we got a good side by side comparison. The MSR's weight with a pot and pan was lighter than the JB with the titanium pot. I believe it was 1 the liter, it was tall and narrow which have it a greater potential of topping over. The MSR boiled the same amount of water faster than the JB, though the difference was not enough to matter much. The big difference was the ability to cook a moose steak (or grouse) without building fire. The JB might have a special pan available but we didn't have it so the we used my pan. One other thing, the lighter on the JB quit working the second day, a match or lighted stick was needed to get it going, a BIC style lighter won't work. That being said, the JB potects the flame better than the MSR. Also, availability of fuel for the JB can be a problem, the Sportsman,s Warehouse in Fairbanks was out of the fuel canisters, it took four phone calls and a trip across town to find the correct ones.
If your only use is boiling liquid, the JB would probably be my choice. However, I use my stove for more then boiling liquid so I will stay with my 20 year old MSR, it has always worked.