I saw Ozawa many times when I was young. For most repertoire, I liked Ozawa very much. I do think that MTT is very good in most modern music, but the SFSO has cut him waaaay back on modern music. He's also good in French rep., but Ozawa is equally good if not better with the French. After Ozawa, we had Edo De Waart.
In general, De Waart wasn't all that great. But he did have a real knack for Mahler (he's like a more positive, less dour Haitink). De Waart made no attempt to over-streamline the textures of his Mahler, the way MTT consistently does. Anyway, I like De Waart's recorded Mahler cycle very much - certainly far, FAR more than MTT's. After De Waart, we had Herbert Blomstedt. Blomstedt didn't do a lot of Mahler here, but what Mahler he did do, he did very well. To my ears, Blomstedt was a musician's musician. He was also a very friendly and down-to-earth person. Strangely enough, Blomstedt was quite good with modern music. Needless to say, he was great with Nielsen, Sibelius, R. Strauss, Bruckner, and Hindemith, as his Decca recordings give testament to. Then there's Tilson Thomas.
I'm not saying that MTT is the worst conductor to ever hit the planet. But I do believe this: a conductor's personality EVENTUALLY leaks through to the music. I'll allow you to draw your own conclusions from there. For me, MTT started out as a fairly good Mahler conductor. But over time, he has permitted more and more bizarre mannerisms to come through in his, "interpretations". Believe me, I'm not the only person who has noticed this. I've written about it many times, and it is not something that I'm just making up in my head. To me, it sounds as though MTT has decided that he must out Bernstein Bernstein. He starts with the basic Bernstein interpretations of Mahler, then combs the scores to look for new and odd places where he can add his own bizarre brand of crap to pile on top of Bernstein. On top of all that, we in S.F. have had to suffer through a slick publicity machine that would make ANY knowledgeable music listener sick to their stomach. L.A. is mimicking the same kind of machinery with their handling of Dudamel. It's complete nonsense. Anyway, just go through MTT's "interpretation" of Mahler 8 - it's just full of the kind of nonsense that I'm talking about.
I saw MTT do his first M8 in S.F., and it was fabulous. It was a straight forward, no nonsense performance that had a tremendous ending to Part II. Then I noticed that he was changing things the second time he put on M8 in S.F. As a result, it wasn't anywhere as good. This latest go-around has even more MTT-isms to it. On top of all this, I say this too: MTT and the SFSO have pretty much crammed Mahler down everybody's throats here. I know that that's a strange thing to complain about, but as result, MTT and the SFSO have actually managed to turn a lot of local people off to Mahler. How smart is that? You have to understand, they've been repeating Mahler over and over here. To my ears, it's all too slick sounding by half. His Mahler 7th sounded like a Broadway pit band performing a concerto for trumpets. By "Broadway pit band", I mean that it sounded kind of small and overly chamber like. It also just sounded plain slick.
Then, about a year later, I saw Rostroprovich perform Shostakovich 5 with the SFSO. It sounded like an entirely different orchestra - it was like listening to Philly in a good, live performance: HUGE strings; plenty of bass; strong low brass; tangy woodwinds - I couldn't believe that it was the same band. So, I'll leave you good people with this final statement: I think you'd be foolish to pay a ton of money to get the last and final installment in MTT's Mahler, just to get some of the shorter song cycles. For not a whole lot more money, you can get EMI's complete Mahler edition box (with outstanding vocals). You can draw own conclusions from there.
And, by the way, I thought that Zinman's S.F. Mahler 6 was vastly better than MTT's, even though he performed it sans expo. repeat. That was maybe three years before MTT's.