Wyn Morris (1929 – 2010) was especially acknowledged for his interpretations of Gustav Mahler's works, which he recorded almost complete during the 1960s and 1970s. He was the first to record Deryck Cooke's second performing version of Mahler's Symphony No. 10 in 1972, only the third time a recording of the work had been made. His recordings remain in the catalog for study and enjoyment. Once described as a "Celtic Furtwängler", Morris was an inspirational and at times spontaneous musician.
It is a reading with a uniquely radiant atmosphere and one that I would urge you to add to your collection even if your instinct is to trust to grander symphonic visions and bigger names. - DSG, The Gramophone
It is a worthy contender and I recommend it. - Tony Duggan
Contrary to his recording of Symphony no. 4, Maazel’s recording of Mahler’s Symphony No. 5 get divided reviews. My opinion is pretty much like this one from Amazon.com:
This is one of the best Mahler 5 recordings I have heard. The Vienna Philharmonic sounds absolutely fabulous. Maazel's has recorded the whole Mahler cycle with Vienna. The performance of Mahler 4 has become very well known. The Mahler 5 seems to be not as popular. This might be because Bernstein also recorded a great live version with Vienna as well. Maazel's interpretation of the piece is very balanced and clear. Maazel brings to me what is a slightly more clear approach to this music, but still with great climaxes. I really like the opening movement and the third movement scherzo. The balance between all the sections is really amazing. You can hear every entrance and every voice. This is a triumph of the players and to the Sony recording engineers. I would highly recommend this Mahler recording to anyone.