I really liked The Year of the Flood, but it is a bit different from Oryx and Crake.
There is similar forward and backward progression in this book, as there was in Oryx and Crake, but it's less pronounced, and less edge-gripping. That's simply from the fact that in by reading Oryx and Crake, much of the mystery has already been broached.
The ending takes you right to where we left Jimmy/Snowman on the beach, and Flood ends probably not more than an hour after the resolution of this scene.
In a way, Flood is written to gives background for life outside of the compound Jimmy and Glenn grew up in. Additionally, the Gardeners, the zealous religious community, devoted to respecting the earth, influenced the design of the Crakers.
I thought there is perhaps more influence on Glenn from the Gardeners. May he have had some belief in the Gardeners? I don't think his ideas were truly separate. He created his own Flood, although not in true Gardener style, considering what Zeb and a few others were doing to cause a little bit of chaos.
I liked how secondary, minor characters in the first book are now main characters in the Flood. I wish I would have paid more attention to them.
I could not remember Brenda "Ren" at all for the life of me. Amanda I did remember, due to her interesting art escapades.
There was a lot of subtly with the main female characters: Toby and Ren. Toby is tough and puts up a large wall. She hides a lot of her emotions, and we as readers don't really even get to see many of them; Toby rarely shares. Even though Ren is shallow, she is truly just an inexperienced person, trying to find her individual self. Atwood makes her extremely likeable, although when I thought back about her, there wasn't anything extremely compelling about her necessarily.
In fact, when I think about Jimmy, he is a rather ordinary person. Atwood is really marvelous at creating unique characters.
Think of this story as an interlude to where you left off. I can see how some people were let down. There isn't any resolution from the last book. However, you get more of a world view compared to Jimmy's narrow vision in the first.