[NB: This is a comparison between two biographies: Taibo's and Anderson's].
For detailed insight on the dynamics of the Cuban Revolution, the historical context, the complexity of events on an international scale, and Fidel Castro's strategic and political wizardry, Anderson's book is outstanding.
However, in depicting Che's "World" so brilliantly, and by dedicating a third of the book to his life before the Cuban revolution, Anderson has forsaken many details and, sadly, some intimacy. "The enormous gesture that was [Che's] life" (to quote the famous song) remains an... incomprehensible gesture. For that extra touch of colour and a more intimate portrait, I would recommend Paco Ignacio Taibo's "Guevara, also Known as Che" (published in the same year). Not only does Taibo focus on Che the revolutionary, but also writes, essentially, through his protagonist's own writing. To quote Taibo, "Che's own words... There is no way to approximate that narrative tone, that incredible sincerity, and that caustic sense of humour."
Whilst Anderson dedicates many pages to Ernesto Guevara's youth, Taibo quickly gets to the Cuban Revolution. Every phase of Che Guevara's life as a revolutionary, including his two ill-fated ventures abroad, is covered in greater depth. Taibo's biography undoubtedly lacks the "scoops" contained in Anderson's book, as well as the vividly-described (and vital!) context; however, it is less "macho", and it offers a more profound portrayal of Che Guevara the man and thinker.
One criticism I have regarding Anderson's book is that he seems to opportunistically - and sometimes blatantly - pick positive and negative points here and there in the name of "convenient" objectivity (perhaps to make the book palatable to a wider - read "larger" - audience). In his selective choice of anecdotes he comes across as rather self-conscious and calculating. Conversely, Taibo (like Castaneda in "Companero", another well-known Che biography) writes more spontaneously: his objectivity is not contrived, and he is more interested in understanding Che Guevara, defects and all. Taibo's book is by no means naïve or sentimental: he endeavours to portray Che Guevara as he would have been seen back then, rather than with today's condescending hindsight (which is what Anderson does).
To conclude, both biographies are excellent in their own ways. Although the crucial details are similar, the authors' perspectives couldn't be more different. For this reason the books beautifully complement each other. They should both be read.
[For those interested in reading more, aside from Taibo's book, I would recommend Che Guevara's incredible Bolivian Diary. Castaneda's biography, "Companero" is more concise and not so reader-friendly, but the author is very clever and provides some insightful analyses. The much-awaited "Evocacion" by Che's widow Aleida March has just been released (yet to be published in English) and I would recommend this mainly for the poignant farewell poem that Che wrote to her shortly before he died (I am sure his biographers would have loved to get their hands on this). A short but moving account written by Che - "La Piedra" (about his mother's death) - is now freely available on the internet.]
UPDATE: I have come across a "revised & updated edition" of the book in Italy - has this new edition been published in English?