I have the Stenz box set and have now listened to all except the M10 Adagio. In general, they are strong performances, and antiphonally divided violin sections are always welcome in Mahler. It strikes me as odd, though, that at medium and higher volume levels, contrapuntal details that are audible in many other recordings, even older ones, tend to be masked. Related, and also not helpful, is that the horns tend to be watery, and I noted instances where horns and/or trumpets should punctuate the texture, yet rhythmically and harmonically they seem to be buried.
I have enjoyed this set and will continue to do so, with the above caveats. I'm curious if the same problems are present in SACD surround.