It's all personal preference. I'm on the 737 and started out with the ear mold and hated it. Went to the clarity aloft and liked it better but thought it was uncomfortable and a hassle to remove when getting up to get food/bathroom break/etc. Finally went with the Bose Aviation X. It's great when the CA also has a full headset and we use rubber bands to keep the intercom hot, especially down in Central America and the Caribbean. Much easier to understand ATC. If the CA doesn't have a full headset I just move the left ear back so it sits about halfway off my ear. There is a sweet spot where you can still hear the CA, still get sound in both ears, and reduce most of the wind noise.