for digital cameras, they are good... they can discharge some high amount of power for a while(to charge flash e.g.) but cannot really provide constant current over a long time.
At Walmart the Duracell Ultra is about 1/3 the price of the Energizer Lithiums. If you are expecting cold weather the Lithiums would be a better choice, because they will probably last at least 5x longer in colder weather. From what I've seen the Duracell Ultra definitely lasts longer in flashlights and is a good choice when you don't want to bring as many spares. Otherwise just stick to normal alkalines for normal use.