Can't really fault these. They are basic, with a two angled operation; flat or slight downward slope. The material used seems fairly hard wearing and correctly absorbent for the job.
In terms of sound, my monitors (M Audio BX8) sounds much punchier in the bass end. Tighter and more direct. job done.
Indeed as other people have said, the Thomann logo easily comes off, in fact mine fell off before I'd even mounted them, removing them from the packaging. But I really don't care, purely a cosmetic consideration.