First of all, here's what I don't understand: when people say Brahms "looks good on the page, but...". I don't even really see how that's possible. They either flipped through a score at a music store, bought it because all the little notes and stems looked pretty, and went home and tried to conduct it with disappointing results: "wow, that page looked really nice, but little Skyler wasn't hitting the bass notes... Brahms sucks"; or, just by looking at the page, they are actually capable of transposing several instruments written in different clefs and key signatures, are aware of the various timbres of all those instrument at different marked styles of playing, and have the musical knowledge to know how those combinations of sounds will translate over time - in which case they would in fact be capable of telling whether or not a piece of music really looks good on the page, and should also be conducting orchestras. But the vast majority of people who really are capable of that and do actually conduct orchestras seem to love and perform Brahms regularly. So I guess I don't really understand what people mean by that phrase but I'm open for enlightenment if anybody else gets it and wants to share.
As for the requiem itself it is beautiful, deep, and personal music. Brahms had an immensely expressive harmonic palette and he knew exactly how to use it to pull listeners in and manipulate their emotions, and that is really what he's doing in the Requiem. He was just as advanced as Wagner with his harmonies and chromaticism. Where they differed was that Brahms believed in the intrinsic beauty of classical forms and the progression of the tradition of thematic development, just as his heroes Bach, Beethoven, Mozart, Schubert, etc. had, which gave his music its clarity and sense of completion and perfection, while, due to his later place in history, he had the benefit of the Romantic period's harmonic explorations to give his music its emotional depth and intensity.
One reviewer claims that Brahms didn't have a penchant for melodies, and regardless of the fact that I don't agree with that, I also think it's important to point out that some movements in this piece are not meant to be sweepingly melodic, but instead very powerfully emotional because of the harmony. This is lush, romantic music, not dry and academic. Appropriately heavy and pensive at times, and those are the most powerful moments of the piece. It's about struggling with mortality, comforting those who are left behind after a person's death - it isn't really a traditional requiem, it's an existential dilemma set to music, using bible verses specifically chosen by Brahms because they illustrated how he felt in relation to his own mortality/sadness in coping with loss, and all of humanity's struggle to come to terms with that.
Some of the 5th movement text:
"And ye now therefore have sorrow...
Ye see how for a little while I labor and toil, yet have I found much rest.
As one whom his mother comforteth, so will I comfort you. . ."
There are reasons why this work is very popular - it is beautiful and affecting, and touches a universal and personal concern of all humanity.
On this recording the slower movements are great: 1st, 2nd, 4th, 7th, totally sublime. The 6th movement, though - it's powerful most of the time, but also a let-down: the brass sounds amazing, and Klemperer really uses them to build tension with those high clustered dissonant notes. But for some reason he builds up to these really intense moments and then cuts the tempo right as the next section begin. It sounds strange and anti-climactic and it's a bummer because it otherwise sounds really impressive.
I would purchase either this or Claudio Abbado's versions, or both. I don't like Karajan's at all, it's ridiculously slow and bland (and I consider him to be the best interpreter of Brahms' symphonies). Bruno Walter's is fast. REALLY fast. And Gardiner's is pretty good. Right now I'm torn between Abbado's and this recording because Abbado's sounds more polished and beautiful, but less balanced. The woodwinds and brass are overpowered by the strings and, although it still sounds great, you realize which sonorities are missing when you compare it to this one.