Since I'm recently retired, I have to watch how I spend my slush money, and can't buy every Mahler symphony recording that comes along.
In addition to this forum, I'm going to have to take into consideration not only what people say here, but elsewhere, before I spend my decreased funds for any new recordings, Mahler and non-Mahler.
Since I live in the DC area, I recently bought the Gergiev M8, since that recording has the Washington Choral Arts Society involved, and I recognize some names listed in that group that I sang with years ago in other choral groups that were listed currently as Choral Arts members. If the Gergiev M8 had gotten "thumbs down" all around, I probably would not have bought it, but I get the impression overall that it got about a 6 (maybe 7) out of 10. The fact that Gergiev used brisk tempi made purchase of the recording all the more better economically, since it fits nicely on one disk. About the only one thing that I would have to say critically of the recording is that I believe St. Paul's Cathedral wasn't the most ideal place to make any kind of a recording. If I were in the audience during the concerts, I probably would not have been able to understand any of the words sung by the choruses, but close-up miking helps compensate for that.
Wade