Well, I've already made a comment on the undeserved 3* review which was basically an erroneous complaint about 'downloading' the music with absolutely no mention of the music, performers, or the quality of the recording. Herzogenberg was a friend of Brahms (and his wife a piano pupil) - I now own about a half dozen discs of this 'little known' composer, all chamber & piano works. Of course, his music is late romantic and Brahmsian w/ some reviewers stating the compositions not quite up to the standards of the 'better remembered' composers of the era.
However, these Piano Trios are well composed w/ pleasant melodies & phrasing throughout the works; the ATOS Trio are into these works w/ dedication and plenty of gusto! CPO as expected produced an outstanding recording - the musicians are in your listening room. Now maybe the music is just 4* but the performance & sound are certainly 5*, thus the reason for my rating. If you like late romantic chamber music, Brahms, and the thrill of discovering unknown composers, then give Herzogenberg a try!