As a contest SSB operator, headphones with a microphone—a headset—are very important to me. The most important criterion for use over several hours is comfort—no pressure points on the ears or head. My favorite Manta MM40s fit me perfectly, but years of use have practically worn them out.
On the recommendation of Jirka OK5IM, I ordered the KOSS SB-40. He faced the same problem and tried out a number of headsets before finding one that suited him. My first impression of the headphones is excellent; they really fit great. They’re larger than the MM40s, and the cable is thicker. The sound reproduction is clearer and more dynamic. The isolation from ambient noise isn’t perfect, but it’s noticeable. However, it fades into the background when there’s noise or incoming signals.