My xm4 are about to die and just around when these were released. My leading theory is their update or something is remotely killing mine.
Sometimes there’s a crackling sound on both and the left earbud touch has become shaky occasionally gets disconnected.
Based on reviews the newer ones are lighter, smaller (maybe too small for some) and has a more balanced sound signature with higher detail retrieval. Not exactly worth the upgrade but the higher SQ is noticeable.
Bass is less bloaty, mids have been brought slightly forward and highs are clearer. Imo looks cheaper with the glossy finish too. Didn’t find anything about ANC