Chuck as a TV show has had a tough time, carried only by it's devoted fans to season renewal, and it's budget scuppered by poor ratings. It's nothing short of impressive that it made it this far, and the series certainly found a perfect time to end.
Following season 4 - the worst in the series, particularly the directionless second half - Chuck 5 shines. The writing is exceptional; there's tons of character development, and the series packs a much harder emotional punch than any of the others, as well as establishing a real sense of fear and jeopordy at times. It's not quite as funny as it has been previously, but it doesn't necessarily need to be, as it often enters into pretty dark and violent territory (there are still a good few laugh-out-loud moments however). This series' biggest problem comes in it's insistence to tie up plot strands far too quickly - what can go from being a huge threat to the world at the beginning of one episode is often thwarted somewhat effortlessly by the end - sometimes resulting in the disappearance of tension just a little too quickly. This is a small flaw however, in a thrilling season that is otherwise consistently perfectly cast (Yvonne Strahovski is particularly fantastic), exceptionally written, and had me in floods of tears in numerous occasions towards the end.