Common consensus is that Heroes Jumped The Shark
after the first season. I tend to agree, which is why, when I re-watched the series, I stopped at the end of Volume 1 because the others are lame.
The first huge, glaring hole in the first season is Nikki. Seriously, her entire arc is stupid. She has no superpowers. She has a serious psychological disorder, and she needs help. Yes, I know she technically has...super-strength, or something boring like that, but she never uses it, and it's never relevant to her narrative at literally any point—when your main conflict is "I blacked out, and when I woke up, these guys were dead," it's not the "...and I used my Super Strength
to kill them" that's the surprising part. The surprising part is how you committed multiple murders and don't remember it.
You could have killed them in the Billiard Room with the Lead Pipe for all it matters. So what's the point of even having her on the show? She adds nothing to the main conflict of the series and she doesn't have any self-discovery development about her superpowers (which, again, she never uses, ever) like the other characters do. The series would have been better off without her.
Another problem is that this show was written as a weekly serial drama, and it shows. Every episode has to have a twist or a cliffhanger. I suppose this is fine when you're watching an hour a week, but on DVD, it feels rushed and, if not poorly-paced, at least suboptimally-paced.
Hiro is fun to watch. He plays off of Ando very well; their sections are consistently enjoyable, with the possible exception of the finding-the-sword thing, which seemed...pointless. Peter's sections are usually good because it feels like he's always advancing the main plotline and tying the other characters together. Sylar is a good villain; The Company is not. I don't think the writers really knew what to do with The Company. That whole plotline never really had a satisfactory payoff; it's built up as a vast, shady, worldwide conspiracy and...well, it never does
much of anything. Kidnaps people. Tracks them. Acts mysterious. Derails Matt and Mohinder for half the volume with no real reason. No, Sylar is a much more interesting bad guy to watch.
So, eh, it's okay, but it didn't hold up too well for me on the second viewing. Still the best volume, but...eh.