Das Rheingold--Version A and Version B

Sometimes I read these things and wonder a) if critic A and critic B went to the same performance, and if so, b) how two very knowledgeable people who are for the most part, fair reviewers, could have such drastically different appraisals of the same performance.

Critic A gushes about the performance, and writes a lovely review, while critic B doesn't write a scathing review, but doesn't seem convinced.