It's not easy to find in-ears which fits well and a has good isolation and a good or natural sound. I think the Nebula 2 has all. The sound [double bass-vocals-violins-percussionis and acoustics] is close to the sound I always hear in a concert hall.
For me the sound and the fit is better than focal sphear or rha t20. The pure sound is close to the pure sound of the AKG k3003 but the Nebula2 has not the overdone emphasis on the treble.