Donald Satz wrote (September 2, 2004):
Daniel Barenboim is not readily associated with baroque keyboard music, and the reasons are apparent when listening to his interpretations. Barenboim has tended to give baroque music a romanticized slant that doesn't fit well with the historical record or the likely aesthetics needed. Further, he can also engage in some odd mannerisms entirely beyond the scope of the scores and the baroque idiom.
Having said the above, I did find his recording of the Goldberg Variations interesting for its distinctive approach while also being exasperated with its many peculiar quirks. The good news for the Well Tempered Clavier is that Barenboim eschews the quirks; the bad news is he also is not distinctive. The fact is that the interpretations are mainstream with little new to say about the music. The new recording is neither the best nor worst Well Tempered Clavier Book 1 on piano I have heard over the years. It doesn't come close to matching the artistry of the sets by Richter, Gould, Tureck, Gulda, Fischer, or the new Fellner on ECM. Conversely, it is much better than the emotionally superficial set from Roberts on Nimbus.
The two words I feel best describe Barenboim's performances are 'pristine' and 'soft-spoken'. I can't say he's particularly warm and affectionate like Fellner. Concerning emotional depth, he can't compare to the exploratory Tureck. On the basis of excitement and thrills, he is well below Gould, and the precision of his readings can't match Gulda. However, Barenboim uses every opportunity to play the music in a fresh and soft manner. Of course, there are many preludes and fugues that require great tension and powerful utterances; Barenboim does well in this area but sometimes is overly restrained as in the Prelude in C minor where he doesn't accept the music's great strength until the conclusion.
I do need to back off a little concerning the soft-spoken trait, because there are quite a few times when Barenboim's lower voices are too demonstrative and aggressive. What I find inexplicable is that this happens during 'soft' periods when the upper voices are pristine. Then all of a sudden, there come those lower voices sounding as if they are spoken by crude professional wrestlers. The result is a loss of the very mood Barenboim intends and a skewing of the balance of the musical lines. The sound quality isn't great either. The soundstage has a great deal of air, most of it wet. This makes it difficult to hear the fine detail among Bach's voices, and that's not good.
Frankly, I don't find Barenboim to have much affinity for Bach's music, although I imagine he would strongly disagree. Because of Barenboim's fine pianism, there is much to enjoy in the set. However, he doesn't convey any particular message, and the sound world he offers has little consistency.
Don's Conclusions: In a highly competitive field, Barenboim's set is not one of the more rewarding versions of the Well Tempered Clavier Book 1. I can give it a very mild recommendation, but I don't believe the set warrants its premium price. If you're looking for a recent piano version, my best advice is to look to the Till Fellner set on ECM.