My friend has one for about 3-4 years. Attractive, good quality and reasonably priced. Beval carries them which is how she got hers as a barely used demo very cheap. She is very happy with it and rides multiple horses, it gets lots of use.
A nice saddle for the money, roughly on par with the Beval Natural or the Beval Artisan. (In fact, the same Argentinian manufacturer who makes those saddles also makes the Colbert Brothers saddles). Like the Natural and the Artisan, Colbert Brothers presents a nice budget alternative to buying a Butet. In terms of quality, I suppose you could also compare it to the Arc de Triomphe Gazelle, Equipe Expression, or the Pessoa Heritage Pro.
As with the Beval/Butet tack, the tree is on the narrower side compared to other French brands (typically 4" across the gullet rather than 4.25" or 4.5" which is more typical for French brands like Devoucoux, Antares, CWD, etc.) Also, don't overpay for it. The low brand recognition in the US = low resale value, not necessarily in line with its quality.