Most third-wave ska is basically pop-punk with horns. The Mighty Mighty Bosstones are no exception to this rule. Most everything about Let's Face It is slick, homogenized, and safe.
The one thing that redeems the Bosstones from the rest of the soundalike third-wave ska refuse (Reel Big Fish, Less Than Jake, etc.) is a respectable horn section. They actually integrate the brass pretty well with the music in most of the songs (ex. The Rascal King, the title track) rather than just treating them like an add-on. However, the latter half of the album is more guitar-driven, and their take on punk is rather pedestrian. If it weren't for Dickey Barrett's distinctive raspy voice, this would be any other third-wave ska outfit.
I'll admit, I used to dig this band. But it doesn't take long to get tired of them or their contemporaries. Operation Ivy is the exception, and that's because they were a punk band first and a ska band second, rather than some half-arsed combination of the two. Get Op Ivy's single-disc compilation Energy, and you can safely write off third-wave ska after that. For real ska, you're better off checking out English two-tone (second-wave) bands such as the Specials and English Beat, or looking even further back to '60s bands like the Skatalites.