Schiit Freya Plus tubes and tube rolling

Hi All- I’m about to get a Schiit Freya plus tube preamp- and have read with interest some of the thoughts on Tub Rolling. However, it seems that Schiit has replaced the tubes in the Freya with JJ tubes, because they feel that they are across the board better than what they had available before. They also dropped the Russian Tung Sols that were previously an upgrade option. They still carry the Russian NOS 6n8s tubes as an option. 
Thoughts on the JJ tubes? Do you think they really are so much better than the Tung Sols? If I were to get some additional tubes to tube roll with- that are equal or better than the JJ tubes- do you have a recommendation? And a link to where to get them? Thanks!