XP-G2, XP-L HI, and 219C are different models of LED. The XP-G2 is one of Cree's most popular LED's used in small flashlights, and the XP-L is one of their most popular used in medium lights. The 219C is made by Nichia, and best known for being available in a high color rendering index (CRI) version that helps make colors appear more natural.
If you're familiar with color temperature, I'd suggest using that as your basis for comparison.
Neutral often is used to mean a color temperature lower than that of sunlight (~5700K), although most often it means in the 4000-4500K range.
If you look at the details listed on the sales page, you'll see two options each for the XP-G2 and XP-L emitters are below neutral, as well as the Nichia version.
I would say if in doubt, the 4000K options will likely be most similar to other lights you may have used that are described as neutral. Between the 4000K options, the XP-G2 will run cooler, and the XP-L will have more output (also more expensive).
The 219C version has a slightly cooler tint, but has such a clean appearance due to the even beam and high CRI that as a neutral white fan myself, I still really like it.