I agree that that LSO M6 is excellent, and during my most recent M7 obsession, I thought his BRSO recording was top of the class. His Pittsburgh Shostakovich 8 is, IMHO, one of the best recordings of anything ever made, and his Philadelphia Shostakovich 10 is outstanding too.
Here in Chicago, I heard him conduct Shostakovich 7 twice, once with the RCO and once with the BRSO. Both were superb concerts.
I tend to be wary of live recordings because they usually lack the precise execution of studio sessions, but with Jansons, it's hard to tell the difference, the live recordings being just as "tight" as those made in the studio.
I had read that he resigned from the RCO several years ago because health problems prevented him from staying there and also serving with the BRSO. He said he wished to regain the Munich position because they had plans to build a new hall, and he wanted to see that project through.