I only own two IEMs both being 1DDs in the ER2SE and the BL-03. Love em both, and they both see daily use from me, Blon for casual listening and bassy genres, and ER2 for critical listening and vocal-centric music. I sometimes think about buying the IE 600 or one of the big hitter all BA or tribrid sets, but then I remember I got the ER2SE for like $50, and I can't imagine anything out there sounding THAT much better than it for me to be shelling out over 10x what I paid for it.