Hard to say if that's true. But most of the pictures in Berlin come from the third concert, and in Vienna there were only two. People who were in the first concert in Berlin said it was not so good and the third was much better. It always gets more relaxing for anyone on stage the more concerts there are. Also all the solo violin stuff in Vienna is a much bigger challenge for any conductor, to conduct the accompaniment, compared to being on your own for the whole concert.
Also they say, Vienna is harder to conduct, since they play so late after the conductor's beat. That alone can stress a conductor not experienced with them out.
I have a preference for the way Vienna played his music. More inspired, more lively, the players having more ambition to play it, having more fun too.
In the woodwinds there were only the best players in Vienna. Their brass group is unparalleled. The horn sound in Vienna, also the trumpets, mama mia... Much better than Berlin. So well blended and balanced, all the way from first trumpet down to the tuba. Berlin doesn't have that quality. The string sound in Vienna: more juicy.
Berlin was also very good, very precise, but less lively, less expressive.