So very late last night, I played both the M1 and M2 from the Jansons/BRSO box. They're both very satisfactory. The sound quality is quite good. I love Janson's treatment of the slow movement to his M1, even if the Eastern European, Klezmer like dance music is a tad exaggerated (I'll take that over under-cooked!). Unlike Boulez, he doesn't take the Scherzo at a racing tempo either. The M2 is really good. It flows very well. My only gripe here is that the high and low tam-tams are too reticent at the end. But overall, it's quite good. I'm looking forward to giving that M3 a shot on the CD player. If it's good enough, I might scrap the Haitink/BRSO one (but would prefer not to).
I've been critical of Jansons up to now, mainly for being too 'lightweight'. You could say that his major climaxes are not enough of an 'apotheosis'. But as always, the devil is in the details.