I run ECC801S' in a phono stage. It is an extremely clear, dynamic and detailed sounding tube. For me, it has so far lived up to its reputation of being extremely durable and long lived.
But, it would be the WRONG tube if you are looking for a warmer, less analytical sound. On that end of the sound spectrum, I like Amperex Bugle Boys. They are warm sounding without being muddy.