I've seen all 5 so far, this season seems to have the best and most action.
It's a nice 'upgrade' from season 2.
Season 2 wasn't bad, just explained a lot which might be boring to some people, but I liked it.
And Sylar is a good guy, if you care to what he really has to say, imo, he's ok.
It's a disease he has, a hunger and someone else will experience how that is soon too.