Got to be honest, I find a lot of his music very meh. 2nd & 3rd symphonies, and piano concerto are my faves, and Dichterliebe and Liederkreis. But the rest of it, especially the piano music I find over fussy and florid. Like Chopin, but without any decent tunes.
But Brahms might not have happened without him, or more especially without Clara, they are the bridge from the Schubert/Beethoven era via Mendelssohn to Brahms and beyond.