As a whole series, it has a weird on-off structure. Season 1 is good, the classic; 2 sets up 3; 4 sets up 5. Hmmm.
Season 5 was a weird one, but at least it was kind of closer to 1 and 3 than I feared it might be.
Spoiler
The cyclical nature of Baltimore, with Sydnor becoming the new McNulty, Michael becoming the new Omar and Duquan becoming the new Bubbles was all a bit cheesy and blatant, but it worked well enough I think.
All in all, I can't help feeling season 3 wrapped things up better. I don't regret watching the rest, but it did kind of go out with a 'meh' when it could have gone with a bang if it had stopped after season 3.
Also,
Spoiler
Omar died?! I honestly felt he was the one character in The Wire who might live forever. It did cross my mind that he might be bumped off, but I kind of thought they wouldn't dare. All credit to the writers for making the deaths in this series so unexpected and sudden. Prop Joe, Omar, the annoying bint Snoop, even small fry Cheese at the end. I didn't see them coming.