Imo the problem of GoW3 is that the second half of the game is weaker then the first. I starts with a bang, but after that it never reaches that level of awesomeness again. I even hated some parts like the whole giant crates section, it's just unimaginative leveldesign.
Overall i thought the story was the best in the series. Maybe a tad too much "double crossing", but good at tying the whole series together. One thing that bugged me though was the whole damn game was focused on getting to the Flame of Olympus.
1. Kratos damn near killed Zeus in GOW2 so why does he need this really?
2. He's killing off Gods one by one, So uh maybe he already HAS the power to kill a God?
3. He had the power in him the whole time. lol
Other then that i thought it was cool.
I do agree about the second half though, labyrinth slowed the pacing way too much and was a poor build to a final boss.