What is the best sounding Mahler symphony cycle?

For fans of the Fischer cycle, try the live recordings of Tennstedt with London Philarmonic — in many instances, simply breathtaking!

I really enjoyed listening to the 
Tennstedt/LPO on Qobuz. It's a very limited selection, so I think I'll go for the cycle that's available on Amazon.

Valery Gergiev's Mahler cycle with the London Symphony is available in a 10 SACD box. LSO - 0730. Live performances! I have it!

I haven’t heard Gergiev in Mahler, but I really dislike the sonics on all of the LSO Live recordings with which I am familiar.  There is only so much that can be done with that Dead Concert Hall, the Garbage Can.  Let’s hope that Simon Rattle succeeds in getting a new Hall built.
  I really like the Berlioz that I have heard from Xavier Roth with his period group.
   Tennstedt Mahler is something that I have never quite developed a love for.  I do have his Fourth, with Lucia Popp as the soloist, but while I’ve had some people praise his live performances to the skies, for me he sounds sternly Teutonic without the leavening Irony or sufficient Viennese Gemutlich.

@schubert , I'm listening to the Fisher via Qobuz. Really an excellent reading of Mahler. And the sound is outstanding; very well mic'd with ambience of the hall. 
Thanks for the recommendation. Possibly the best I've heard in years.