Like others maybe, I came to watch this film after watching the series, so maybe my view was tainted a little from already knowing the story. There is no way in the world you can cram the same level of detail from 20-30 hours of TV into a 2.5 hr film, and I wouldnt expect them to, but there are certain areas which I think are skimmed over a little (relationship with Ze Carlo, the Shady 'state' representatives etc). Still a very good film, but even knowing the plot and characters I found the second half of the film a little confusing and skipping from place to place with little explanation. If you have watched neither the film nor the series I would probably do it the other way round to how I have, watch the film first as it was obviously made first, and you can view it without preconceptions. If you enjoy it, and I see no reason why you wouldnt if you like this type of film (would you be reading his otherwise?) then get the series to put a bit more meat on the bones.
I wouldnt mark it down purely because it isnt as detailed as the series, but have to mark it down a bit as I feel it loses its way a little second half. Still a very entertaining film and even at 2.5 hours it doesnt seem like it is dragging. In some ways I wish it were 4 hours long and a bit more detailed, but you cant have everything eh!
The plot isnt anything earth shattering, but it is a generally well told yarn. It is the characters that make it, and watching their rise and how the power/money has an effect on each of the main players in different ways is what makes it such an interesting watch.