I think the Corbin includes price includes having it painted. For what its worthI looked it up and I like the 9.5l capacity, I think the Sargent one looks better, but that capacity would make it my choice anyway, except two things. I already have a Sargent saddle set, and I'm not sure the Corbin wouldn't interfere, especially because my saddle is custom. Also the price is more than three times as high. $300ish unpainted vs almost $1000, wow.
I also looked at the Diopa unit which is like 500 or 600 euros and I think looks a little better than the Sargent, but looks slightly smaller and the access through a tiny slot under the but pad was a deal breaker for me.
You can see the Diopa one on Divadanielle's (I think) project parts bin posts here on the forum.