It is very usual for a person to have a chapped and dry lips. So we tend to look for something that can resolve that problem. Petroleum Jelly or a Lip Balm (the ever so popular, Vaseline and ChapStick) - is one of the few things that would come to our mind. But mind you, there is a lot more into moisturizing. Here are the three classes of moisturizers:
Occlusive
Occlusives creates a barrier between the skin and the air, preventing the skin from losing moisture. Not inherently moisturising, occlusive ingredients like petroleum jelly repel moisture, sealing it in your skin particularly effective when applied to already dampened skin. Petroleum jelly is the most occlusive, mineral oil or silicone. Occlusives are the most common type of moisturizers used in formulations.
Humectant
Humectant is the second major class of moisturizers. It increases the water content of the skin by enhancing water absorption into the skin surface. It extracts water molecules from air and pulls them into the skin’s surface. Common humectants include glycerin, aloe, honey and sodium hyaluronate.
Emollient
Emollients are essential fatty acids, which are found in various natural oils (coconut/ olive/ almond oil etc) -improve the appearance and texture of skin by filling in the spaces between the skin cells and thus contribute to increased softness and smoothness of the skin thus improving its overall appearance. It helps restore your skin’s own water barrier which repels moisture like occlusives
TL;DR
So, in other words: Occlusives keep the moisture until removed. Humectants bring the moisture to your skin, and emollients help repair skin so it can keep the moisture in without the presence of occlusives. A good moisturiser contains all three of these types of ingredient.
Note that these are not pre-made moisturizers, but rather moisturizing ingredients.
My Take
I used to apply Petroleum Jelly to my lips such as the ever popular Vaseline. However, as soon as I did a few research, I have found out that Humectant based moisturizer suits me better, I use the Nuxe Paris Rêve de Miel. Bought it, tried it, and I can say that it is really good as it is not heavy on the lips, does not feel oily and just work. I can use it in the morning and still be on my lips at night before reapplying it again prior to going to sleep.
Now, I have the option to just use both. Put Petroleum Jelly on top of Nuxe Paris Rêve de Miel. You can try, I guess. My lips are on the bit larger side and adding more mass will feel heavier and annoying. I also really hate the oily feeling of the Petroleum Jelly. The Nuxe Paris Rêve de Miel feels like you are not wearing anything and natural to the lips, at least.
For practical purposes petroleum jelly is the best moisturiser. However the best moisturiser really is one you like using and suits you well. Just remember that “expensive” does not equal “good moisturiser”!