Hero Factory is one of the best themes of all time. When I first got into LEGO in 2010, Bionicle just ended, so I had no interest in it. But, Hero Factory was just starting. I loved the first wave, and I also though the Story was good. At the time, Hero Factory was my favourite theme.
Here arw my thoughts on all waves:
Rise of the Rookies: it was great, still used the old Bionicle parts, the story was good, the sets were fantastic.
Ordeal of Fire: Introduced CCBS, which will change forever how constraction sets are made. I also enjoyed it as much as the first one. Good story, powerfull heroes, Strong Villians, great sets.
Savage Planet: in many ways the sets was similar to Ordeal of Fire, just in a jungle environment. The story was better then the one from Ordeal of Fire, so that's a pro. But I liked them as much as the prievous wave.
Breakout: The best of Hero Factory. The story was the best one in the entire theme, the sets were bigger, and better. The only thing I didn't like is that it removed canisters, and introduced that odd bags. But overall, Breakout was the best wave from the entire theme.
Brain Attack: While the sets were not as good as other waves in my opinion, the story was still interesting. I didn't get any sets from this wave, for this reason. Still a good wave though, just not as good as the others.
Invasion from Below: The story was bad, and that is what probably ruined it. But the sets were actually pretty good. (Better then Brain Attack in my opinion). And this new concept of the Heroes being minifigure sized also was pretty cool. I got plenty of sets from this wave. It was good, just the story was bad.
Final thoughs: while inferior to Bionicle, Hero Factory was definitely something that should be remembered. I still have the Canisters from the first three waves, which I use to storage pieces. I think Hero Factory is a little bit underrated. The story was still good, and more accessible then Bionicle, which was mostly told trough books. Hero Factory is a theme that I will always remeber, no matter what people say. That is all I had to say.