For me, for 2020, I was so happy that the Nezet-Seguin Philly 8 finally got released, my capstone to a most memorable live experience of that performance back in 2016, of which I was there, and my wife as well.
I have gotten the Vanska M2, and think it is a very good performance. A return to more normal tempi where the entire symphony can be put onto one disk, as did both Walter and Klemperer. I haven't gotten any of the other Vanska performances.
While the Rosbaud Mahler box certainly is a major addition to anyone's collection, and the performances are difficult for anyone else to match, to my ears, something isn't right with the sound. I differ with John Kim and feel that the sound could be better. I base my complaint on comparison with other Rosbaud sets of other composers that I have in my collection, and big orchestral sound (particularly with Rosbaud's performances of Bruckner Symphonies 2 - 9) is a lot better. I wonder if there was something about the original Mahler tapes that wasn't right, plus it sounds a little like some artificial reverb was added. James Meckley mentioned that he might check into technical aspects of the transfers, but we never did hear anything more from him.
Lastly, in addition to the Nezet-Seguin Philly M8, it was a joy to finally obtain a copy in decent condition, of the de Waart complete cycle, at a REASONABLE price.
Barry, what was your source for the Falletta M8? A private complimentary "donor" recording?
Wade