Rogue Audio Cronus &/or Atlas owners ... TUBES ?

My Rogue Audio Cronus integrated amp is about to reach its third birthday, and I'm ready to replace the original Svetlana EL-34 output tubes. What are your experiences and thoughts ? Stay with EL-34's ?, try Gold Lion KT-77's ?, perhaps EH KT-90's ? See my sysytem for the rest of my stuff. I mostly listen to 1950's - 1960's small ensemble jazz (tons of Blue Note re-issues, etc.)