I also just finished watching Tom Hanks' gangster flick the Road to Perdition. Can't say that I was all that blown away.
Road's not a terrible film; far from it- it's well acted and the photography is wonderful. But I could never completely believe Tom Hanks with his chipmunk cheeks as a dour mob hitman, no matter how solemn and glum he behaved. There was a certain predictablility to the whole thing- I never thought for a minute that there was any chance whatsoever for a happy resolution for anyone involved. Jude Law almost sparked the film a bit with his portrayal of a freelance hitman who supplements his income by photographing his victims, but it seemed like no one was allowed by the director to be even the least bit flamboyant, even Paul Newman, who in his dotage still was able to bring his character to life, and in a strange way was the most charismatic character in the whole thing. And despite the aforementioned excellent Oscar-winning photography, the constant drabness and ever-present rain just became oppressive after a while, making the film a slog in more ways than one.
I didn't care much for director Mendes' last film, American Beauty, either, but it was more of a problem with the characters and the way they behaved towards the world and each other than any problems with his directorial skills. I liked Road a bit more, but it's a hard film to really like and I wanted to connect with it, get caught up in it and really care about Hanks and his family's tribulation, but I just couldn't. Maybe you can...so I say see it, but don't expect to be on the edge of your seat.