I would be more inclined to believe the 73% of audience that liked it vs the subpar 54% approval rating given by the "critics".
A star studded cast fill every scene of this movie. Most notably in my opinion is Brian Cox as Agamemnon, a man driven by his own nepotism towards his brother, and his desire to conquer. Brad Pitt and Eric Bana, both in their physical prime, portray Achilles of Greece and Hector of Troy respectively and create an excellent dichotomy between their rivalry.
Despite Troy's departure from its poetic origins, it's main theme is one of immortality. Right from the beginning there is a wonderful little quote between Achilles and a servant boy who is sent to summon the warrior to battle on bequest of Agamemnon. The boy expresses his fear of battling the great warrior awaiting Achilles, and he looks down on the boy from horse-top; "That is why no one will remember your name." Achilles only dream is to be remembered beyond his years as the greatest warrior in Greece. To die in battle is the only honor a soldier could receive in those day, and was fully expected of them, however only the truly exceptional, or the truly powerful, will be remembered for millennia. The love of the Greek people is what causes the main rivalry between Achilles and Agamemnon, as both are striving to be remembered for eon's after they are gone. It's a beautiful idea, and a constant drive for both characters.
Overall, there are a lot of critics who deride this film for its departures from its literary origin. But I believe, just from a cinematic viewpoint that it is an exceptional tale. Perhaps this film will even aspire a few viewers to go out and read Homer's works. It is a fair estimate that most viewers will watch this film simply for the adventure, and that is where this movie excels.