So why was it so unenjoyable?
Outside of its prodigious length (4 1/2 hours) the film is just flat. No ups, no downs, no tension, nothing...It is a sterile effort from beginning to end. Del Toro looks fantastic as Che, no one could look better than he in this role. Unfortunately that's all he does here...look good. As Che his vocal tone never changes, he talks in a simple slow monotone the entire film, like a wise teacher constantly trying to convey his vast knowledge upon his pupils with no emotion.
As far as the film's history goes...well...it admits upfront that it is based upon Che's personal diary in large part so its not exactly going to be a balanced look at the guerrilla icon. One thing I will credit the film with is that at least it shows both his best known success (Cuba) and also his final defeat (Bolivia).
The praise heaped upon this film at the time of its release in 2008 is in part due to the rise of the Left around the world, particularly in South America, and also within the U.S. itself. When del Toro goes to Venezuela to give screenings to a despicable creature like Hugo Chavez, you know you're riding a wave of socialist revival.
This film will not educate you as to who Che really was as a person nor what his actions accomplished or the thinking behind them. It will merely make you think you're smarter than you actually are when wearing your Che tshirt and hanging out in your local college bar...
More worthy of your time regarding Che:
The Motorcycle Diaries the 2004 film staring Gael Garcia Bernal and directed by Walter Salles. Based on Che's early diaries on his travels throughout South America as a young man this film teaches you more about the true Che in a 1/2 hour than Che does in four plus hours. Plus, its actually enjoyable, imagine that.
Che Guevara: A Revolutionary Life the biography by Jon Lee Anderson. Over 800 pages in length and not a wasted page in it. It is the definitive biography on Che and covers his entire life and goes deep into events in Africa the USSR and elsewhere. A must for anyone looking to speak knowledgeably on Guevara.