Anyone have experience with the Tung Sol 7581a vs. EL34, KT66, KT88, 6L6


I broke down and added another power tube (Tung Sol 7581a) to my collection.  That can get expensive as my Primaluna Dialogue HP Premium integrated has 8 power tubes.   

Why has this tube escaped me thus far?  Why is it not more popular?   Many folks don't sell this reissue tube.  

I think this is a great deal.  I was torn between the lush, thick midrange of the EL34 and the more evenly spread out sound of the KT88.  But the KT88, for all its more correct behavior didn't romance me like an EL34.  

The 7581a from Tung Sol can be had cheap and I really like them.  [I'll spare you all the audiophile terms].  They check the boxes that I was looking for. 

Does anyone have experience, information or knowledge about this splendid tube?  

PS  The next experiment is KT150s but I can't see doing it if I'm gonna lose any of that great EL34 midrange. 
128x128jbhiller
Follow up on this. I tried putting the old Raytheons back in and it was no contest. Existing attributes have consolidated initial impressions and any tiny lack of midband sweetness now seems like a more neutral clarity, if you know what I mean. Tung Sol 7581a are keepers for the moment. 

I did not have good life on a matched quad of Tung Sol 6L6 G big bottle tubes.   They sounded really good and looked cool , but they started to drift and one died after only a few months.   Gold Lion KT66 is a rugged sweet sounding 6l6 variennt
I'm wondering if the GL KT66 hits that sweet spot everyone is wanting. Can't seem to find much feedback tho.