Well, that was a pretty decent start to this volume. And clearly there's a sense of them trying to go back to basics here with the idea that they are ordinary people with superpowers, what with Peter back as an Paramedic, Mohindir as a cab driver, and Matt a security guard, etc. (not to mention the cab scene that echoes the very first episode). You also have characters essentially back to their original roles. Nathan and Angela are the bad guys again, only this time their roles as manipulator and collaborator are reversed. HRG is again rounding up folks with abilities but this time working for the government instead of the Company. Not to mention Hiro and Ando once again poking fun at superhero templates since they now have their own HQ, a mode of transport for Ando, and a costume Ando refuses to wear. (Plus the scene where Ando acts like a pimp daddy with the call girls got a chuckle)
With regards to Peter's new abilities, I think it's pretty obvious how they work. Before where all he had to do was be in proximity to a person with abilities and permanently absorb them (thus racking up abilities) it now appears--since he lost his original powers with the formula--that he has to not only physically touch a person with abilities but also that he can only hold one ability at a time. This is why he tells Nathan "What was the last thing you saw me do?" indicating all he could do was fly. When he touched Mohindir, he lost the ability to fly and replaced that power with super strength; and when he touched Tracy, he lost his super strength (hence why the guard started beating him up so easy) and gained freezing powers. This, I think, is a pretty good move on the shows part because not only is Peter no longer so ridiculously powerful, but he also forces him to think when it comes to deciding which person's ability he has to copy and/or swap.
It also suggests that if Peter's original mimicing abilities have changed, then if Hiro ever gets his teleportation powers back (which given that he no longer has means he can't easily escape after that plane crash) it's very likely that it would limit how far he teleports and the degree in which he slows down time, so no leaping around the world or time travel for him.
The best scene was definitely Sylar against the hunters, showing once again that Sylar is not someone you should underestimate. Although it looks like, once again, the show is going to make him an anti-hero, and I'm not too keen on making guys who are supposed to be bad guys into "good guys" simply because of their popularity. But oh well.