I’ve only heard the older Pass X250 and I didn’t think it was anything special. It sounded just like any other high powered SS amp even a little bright at higher volumes. It sounded reasonably decent with a tube preamp sitting in front of it but so did my high powered Adcom amp. I thought Bryston 7B-ST monos sounded better in the same system. I understand the newer .5 and .8 versions are significantly better but are priced higher accordingly.