Are MULLARD NOS EL34s and LTA ZOTL40 REF worth the price of admission?

I'm considering giving an older Linear Tube Audio (LTA) ZOTL40 Ref amp an audition.  LTA has a factory upgrade that includes upgrading to Mullard NOS EL34s for $800 (or less with additional discounts).  I am wondering if quad set of old-stock Mullard EL34s are worth the $800 price of admission?  I don't pretend to know what anyone else's budget is but $800 for quad EL34s seems like a lot.  If I'm paying the premium, it better be across the board and not just improvements on chamber music or obscure Chinese opera (no offense intended).  Does anyone have experience with either NOS Mullard tubes or LTA ZOTL40 Ref amp?  If so, please chime in.  Thanks.
Sophia tubes, and my search ended
I have NOS Mullard EL34’s and a quad of Sophia Electric EL34ST. The Sophia’s are as close to Mullard EL34 as you can get which makes them the best new production EL34 tubes made but they are expensive.

For you guys that have a new Z10 or ZOTL40, give those caps some time to break-in properly. It gets better.
Andy is fantastic and has the real deal test equipment ;-) an alternate for new and equally of better computer matching is RAM tubes. Roger ( RIP ) a true genius. I run an octet of his matched EL-34 in his RM9 amplifier....awesome sound.