I think there are two main types of sunblock by Neutrogena.
1) marketed as "Ultra-Sheer"with Helioplex ( Gaile Lai ad)
2) marketed as "ure Mild" in transparent plastic box and no TV Ad at all
I used ültra-sheer before but I find it shiny and has this common sunscreen smell. The ultra-sheer is actually a chemical sunblock, the chemicals on which absorbs the sun and you will tend to look darker after exposing to the sun. This is because of the chemicals being degraded by the sun rays. However, this seemingly darkened layer of sunblock can be removed after you wash your face.
The Pure Mild (in the US the baby line is called Pure & Free) on the contrary is a physical block. It is claimed that the micronized metal compounds: Titanium Dioxide and Zinc Oxide would sit on the surface of your skin and blocks the sun by way of reflecting the harmful UVA and B rays.
The recent hype of mineral cosmetics teaches us that these mineral products are the purest and safest. (This I have learn to believe until more studies come out to tell me otherwise).
The above are the main difference.
For me I prefer the Pure Mild type as it give me a more whitish finish ( i personally like this) and the sunblock starts working the second you apply it and you don't have to let it sit for 30 mins before going under the sun like the Ultra-Sheer. Moreover, when you sweat, you see clearly how the white stuff is washed off with the sweat so that it reminds me to reapply to the baby. More importantly, no weird smell. The Pure Mild type is difficult to apply evenly as it is thicker but if you were to go to the beach, you wouldn't mind at all since the white stuff won't show up on the pictures anyways.
Of note, I checked the Mustela baby sunscreen, it is also a Physical block like the Pure Mild.