Well generally films by Bay are high on action but does poorly in terms of the screenplay. Well for this one there was still a lot of action especially in the second half of the film. However the screenplay has improved for this one. The screenplay on this one is actually pretty smart even if the concept was unoriginal given the track record of Bay.
I thought the acting of the main characters was sufficient enough. Ewan McGregor did a good enough of a job. He did a good job in some of the lighter moments of the film. Scarlett Johansson who was great in Lost in Translation does not shine in this one as basically her role takes a back seat to McGregor's character. Sean Bean as usual performed well as the bad guy.
One thing I was rather disturbed about was the rather blatant "product placement" in the film. It was like they were shoving the brands down your throat instead of it placing it more subtly in the background.
Also some of the other actors who were given top billing I thought were under utilized in this movie. The story really revolves on Lincoln Six Echo with bits and pieces of the others.