Best 12AU7?

I really like the mil spec triple mica black plate RCA 5814A I just found. Detailed, smooth, not dull, and not too bright either.

Upscale Audio has very good NOS and new tubes. Check them out. 

Also, Vintage Tube Services - Andy Bouwman. 

I use RCA black plates from 50s in driver position, very balanced and full sound. But I also use Mullards 12AX7 long plates in preamp. Excellent match, anyway, but it won't give the best high frequency extension.

Also enjoying a mil spec grey plate single mica GE 5814A