The performance I saw them do in S.F. on the same tour was MUCH MORE like this London Proms one. I've always suspected that Bernstein held back and took less chances for the Frankfurt performance, knowing that it was being recorded for his DG cycle.
The Vienna Phil. has been involved in three of the greatest live performances I've ever seen: M5 in S.F. with Bernstein (as mentioned); Bruckner 5 in Vienna with Karajan (1981), and Mahler 6 in Berkeley, Ca with Bychkov (about 10 years ago, or less). I also saw Bernstein do M6 with the V.P.O. in Carnegie Hall. It was great, of course, but I actually liked the Bychkov one even more.