I feel the first half of the season was better than the second half - it loses some steam after Tuco's cousins are killed. In a way, their deaths were a shame because that story line was extremely interesting and those episodes were very easy to marathon. Also, the cousins reminded me a bit of Anton Chigurh - frightening and fucking crazy.
At the start of the season, I predicted that either Hank or Skyler would be killed off, and I was almost right with "One Minute." That was such a great episode and I loved the tension with Hank sitting in the parking lot and receiving the phone call. Great stuff.
Again, season three lost steam after that point. As soon as Walt's problems with the cartel disappeared, problems with the season began emerge. There was no real conflict; it was just a lot of Walt standing up to Gus, and Gus giving into his every demand because there is no show without Walt. Also, after the shootout in the parking lot, we don't see a lot of Hank or Marie. I'm not a big fan of those characters, but it seems that the writing staff is running out of things to do with them. Skyler also disappeared after she told Walt she wanted to run the car wash. It's a little understandable, because obviously they had a lot going on with the Jesse/Tomas story line...but still.
Additional thoughts: I hope the show continues to feature a lot of Bob Odenkirk in season 4. He's hilarious and plays Saul Goodman very well. Also, I really enjoy Johnathan Banks as Mike. Obviously they make his character very badass, but I enjoy the scenes in which he has a long monologue a lot more. Great performances from him. Overall, I am loving the series. It's so much more realistic and enjoyable than Weeds (this is like comparing apples and oranges, but they are shows with a similar premise).
The fourth season of Breaking Bad will premier on July 17th, 2011 on AMC.