A few points re: Gielen--
Barry makes a sensible observation when he says that you need to look at reviews in context--that is, in terms of what was available at the time. Since those recordings have come out, and the Mahler explosion (glut?) has continued, there have been individual performances that may be better in certain respects, but Gielen's work certainly stands on a high enough plateau that I see no need to revise my view. As Barry also knows, I am a big fan of Bertini's.
Second, as usual when one is speaking in gross generalities, psanguin misses the nuances in my view of Gielen's cycle. For example, his Fourth is a good performance, but the recording got a "9" rating, as I make perfectly clear in the actual review, because of the sensational performance of the coupling--Schreker's Prelude to a Drama. To say that Gielen's orchestra is not "world class" or the sound isn't to psanguin's taste strikes me as begging the question. As a rule, I never worry much about sound ratings because this is even more impressionistic that opinions about performances. Everyone hears music on different equipment, in a different acoustic environment, and a recording that sounds fabulous in one room may sound dreadful on headphones, or on cheaper (or more expensive) systems. So why quibble about it? Beyond very general issues of balance and naturalness (such as I point out concerning the lopsides basses in Zinman's Mahler 5), the whole issue strikes me as nonsense. If anyone here has participated in an audiophile chatroom, you will know that they make our discussions of performance issues look like perfect examples of the scientific method!
As to the orchestra--again, a generic criticism of no real value. Gielen obtains world-class results IN MAHLER. You will not hear any significant lapses in ensemble, any embarrassing slips, or other mishaps such as mar cycles with orchestras that are theoretically "world class", such as Karajan's Berlin Philharmonic, Bernstein's New York Philharmonic, Solti's Chicago Symphony, Sinopoli's Philharmonia, etc. From a purely technical point of view, Gielen's work is more consistent than any of them (as is Bertini's). These German radio orchestras, as I never tire of pointing out, are often superb, and terribly under-rated. But beyond that, there's a question of idiomatic style, and this is where I think Gielen has few peers aside from Bernstein. He understands Mahler's sense of color, his desire to make rough or ugly sounds, and his willingness to give him what is actually written in the score, better than just about anyone else. One example: listen to the downward clarinet glissando/portamento at the beginning of the scherzo of the Seventh. It's just as written, but you won't hear it to the same degree in any other performance. This is what makes Gielen special.
Finally, my relationship to the Gielen cycle was a interesting. Originally, I was asked to contribute notes to the cycle (for free, by the way, because I wanted to review the recordings so I couldn't take money). I did, and those notes formed the basis of my book on the Mahler symphonies. Gielen HATED the notes so much he decided to write the rest of them himself, with typically incoherent and demented results. He objected to the fact that I "only" talked about the actual music, but neglected the wider philosophical and aesthetic context. So I didn't feel at all bad reviewing the discs and praising them knowing that he detested my work in the first place. Perhaps he hated the reviews too, because they were too kind!
Dave H