I'm personally thinking NOS tubes, I've tried the gold lions in other tube types (300b,12 series small signal tubes, kt66, etc) and yes, they can be good.
I'm really wondering what NOS tubes people have tried, I've not used 12AT7 before so i'm not really sure which are great specially for the money ( i'm not paying $300 each for telies for example). I still want over all good sound from top to bottom but i'm looking for more midrange tone and sound stage depth and width. I find the JJ's if that's what Mcintosh is still using to be lacking in midrange tone and sound stage they are quiet, decent bass and decent up top if not a bit bright. But not like many of the NOS tubes I own.
Also, anyone using 6550's opposed to the KT 88's? I find the KT series to be overall leaner in the midrange compared to other NOS types.