Just finished all 4 seasons in 5 days. The series as a whole is one of the best tv series I've ever watched, the concept is amazing. With that said, season 1 was the best season of any show I've watched. Season 1 always had me on edge. Season 2 was fitting and would have been a nice ending to a great story. Season 3 was pretty shitty, it did not keep my interests and the plot holes were just ridiculous but I still finished it. Season 4 just got to be ridiculous, the first 7 episodes were really boring. It got better towards the ends but the plot holes made me laugh. The final break was a joke and unneccessary.
I remember it later aired right before the short-lived series based in New Orleans called K-ville. I wish Prison Break was not caught in the cross fires of the strike, this series had so much more potential, and that is saying something of an already great show.