His pre Op. 34 chamber music can be heavy handed. It suffers from a complete lack of charm. Even the opus 34 has a bit of that heaviness. I saw Leon Fleisher play it with a quartet who’s name escapes me. The Clarinet Quintet gets my vote as the greatest Chamber work of the Romantic ERa (post Schubert - pre Debussy).
Whoa, pardner, them's fightin' words!
I'll stipulate that the Op. 8 trio (in both versions) has problems. I'll stipulate that the seams show in the finale of the Op. 26. But the slow movement of the Op. 26 quartet is one of his best. The Op. 18 sextet has its flaws, but it's a beautiful first try -- and it's better than Tchaikovsky's sextet (from our argument on a previous thread).
The Op. 25 quartet is a crowd pleaser for a reason. It's beautiful, fun -- and yes! -- charming. I've never failed to see an audience charmed into a standing ovation by that piece.
The Op. 34 quintet, which I saw performed a few weeks ago at the Seattle Chamber Music Festival, may be on the heavy side, but I never fail to find it charming, particularly after the flawless performance I heard.
I'll agree with you about the Clarinet Quintet, however. The Op. 115 is a four-handkerchief piece and certainly one of the monuments of the romantic tradition.