The Bertini Mahler box arrived last week here. I've only listened to the #1 and #5 so far, on floor system. Astounding. The clarity and imaging are superb on my system. I must say, I've liked Bernstein (VPO and NYPhil), Haitink, and some of Karajan. Fingers crossed, I must now add Bertini to this bunch, maybe even as lofty as #2 (beside Bern.). What a sleeper set so far.
I am glad you like Bertini's Mahler so far. More impressions awaited.