Meh, I've had a few different Cliff bars and they're all to sweet for me. But the packaging is pretty robust. I'm not sure if it's as robust as lifeboat rations, though- maybe. The Cliffs definitely make me more thirsty than the Datrex bars, though.

Any of the ration bars will be a pretty minimal, survival-level ration...that's the whole point. They'll be better than nothing but obviously no 3,600 calorie diet will keep you feeling sated for three days. Certainly if you can supplement it with foraged food you'll be better off.

Jerky is a good survival food, maybe the original survival food. I'm a big advocate of nuts in that role, too. Take sunflower seeds for example. A 3.5 oz bag of sunflower kernels has 595 calories, and 525 calories is from fat! I think that's outstanding. Carbs might be easier to access but the energy from fat will last longer. Plus it satisfies your hunger better IMOHO. Nuts pack a lot of nutrients and calories for a small amount of bulk, plus they generally keep pretty well. You will need a bit more water to process them though.