BenM's Super White and SW's Extra White are very similar.

The list of colorants isn't going to help you because #1 you're dealing with 2 different brand's colorants/bases and #2 if you analyze the list of colorants they're basically the same.... from two different brands.

Formulas, the math and chemistry that comes with, are mind-boggling and it's just not necessary to struggle trying to find clues in the formula because there's a better way.

The only way you can compare color, especially colors of white, is to compare color notations. Color notations are derived by measuring the color; you can call it Color DNA.

There is no such thing as "undertones". Every color belongs to a hue family - and that includes whites, grays and blacks. If you want to learn the truth about the much theorized fabrication that is undertones read this.

Extra White and Super White belong to the same GY (Green-Yellow) hue family. Colors of white that are perceived as "just white" belong to this hue family neighborhood of the color wheel - nothing remarkable here.

The colors are nearly the same in terms of Value and LRV - nothing to discuss here either.

Where they differ is Chroma. Extra White has a tiny bump more Chroma than Super White.

And that's the answer to your question about which one is more neutral.

Super White is more neutral - just barely - than Extra White because Super White has less Chroma.

They're both pretty. Legend has it that Super White was the template for Restoration Harware's "The Right White" paint that they sell and use on the trim/doors in their stores.