Because I don't speak any German, I wasn't put off by the Gergiev's Slavic soloists (though if I had I heard West Side Story sung with a pronounced London accent instead of something from NYC, I might wrinkle an eyebrow). For me the soloists are like instruments in the orchestra: I don't speak "flute" but I know I like a clear sounding flute and not a breathy, wobbling one: I basically feel the same about tenors and sopranos whether they are dealing with texts in German, Russian, Swedish, or Swahili. Claiming no skill in any other language except "American" English, I wonder, are others as blissfully ignorant of the language infractions that are being committed in recordings like this one?
That pretty much sums up how I feel about voices, and especially pronunciation, in most Mahler symphony performances. Perhaps this is one of the big advantages to being the average blissfully ignorant American (in terms of foreign language ability that is).
For my money, this is a solid 10/10 recording in multi-channel SACD. There are always a few things that I dislike in ANY Mahler performance, but the Gergiev gets overall good ratings from me across the board: it is a very good combination of orchestral playing and execution, flexible conducting, lots of details, very good solo singing, a FABULOUS ending, and great multi-channel sound. Frankly, this is probably my top recommendation to a non-Mahlerian that wants to know about M8. All of my other favorites - save perhaps the Lennie M8 DVD, have something that would make me think twice about recommending it to a newbie. And even the Lennie DVD does not have particularly good sound.
So off the top of my head, these things bother me about my top tier M8's:
Chailly (slow tempi at the beginning is underwhelming -- although it pays dividends later; I'm not a big fan of the Gretchen soprano)
Sinopoli (some truly dragging tempi throughout Part I)
Nagano (Gretchen soprano is awful)
Bertini (I don't particularly enjoy some of the soloists voices -- although none are less than decent)
Solti (ending lacks excitement -- although has lots of toy organ)