The show is very well written and acted. Miller and Purcell are definitely the leads, but there is a very large ensemble cast, and the show does a great job balancing character storylines and screen time so that there are episodes in which Miller and Purcell take a back seat. The supporting cast in season one includes Sarah Wayne Callies as the prison doctor who is (unknowingly) integral to the plan to break out and Stacey Keach as the prison warden. The show does a great job of giving all the characters, inmates, guards, and the like, gray areas so that they are not all good and not all bad, and the entire cast does a great job portraying that.
The Blu-Ray set is a six-disc set. The A/V quality of the set is outstanding, and it contains a lot of extras. Those include commentary tracks on select episodes (sometimes more than one commentary track for an episode), deleted scenes, and about an hour's worth of behind-the-scenes and making-of material that includes cast interviews and showrunners, how they came up with Michael's tattoos, and a featurette on the history of Joliet prison where the show is filmed. So, if you like watching the bonus material, you get a lot here. Overall, the show is a good serial drama with great acting and writing. The showrunners had the entire plot planned out, and you get the idea that, even when twists are thrown in, it is not just ad-hoc and done purely for shock value. Given that it is set in a prison, there is a lot of violence as well as themes of racism, sex, abuse, etc., but it does not come off as gratuitous. It is definitely a good, binge-worthy show and worth checking out.