What is the best sounding Mahler symphony cycle?


Folks... I love Mahler but my two versions of the 5th sound very low-fi. I am looking for a well --- really well --- recorded 5th on redbook CD --- or better still... a whole mahler symphony cycle that is audiophile (or... near audiophile quality.

Any help would be appreciated
robsker
An excellent series so far is Francois Xavier-Roth on Harmonia Mundi, sonics and performance.
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!