I'll be honest - what with the hype going on about these books, I was a little hesitant... but in the end, I can never resist a YA series with what seems like a good plot and an interesting setting, so I picked up Cinder. And then I found myself unable to put it down again. 
 In any case, this book had me hooked right from the start. The world in which everything happens is so interesting; futuristic, lots of technical and sci-fi stuff, as would be expected, with a highly contagious disease killing people left and right and a bunch of not-quite-human people from Luna, the moon, trying to make peace by coupling their evil and creepy queen with the prince of the Commonwealth, one of the six "countries" left on Earth. Amidst all this, there's Cinder. 
 Like the fairy-tale character she was based on, she's basically a slave to her stepmother and stepsisters, although she is very close with the youngest of them, who is kind. Cinder, however, is no helpless little lady who doesn't dare stand up for herself. She's a cyborg and a mechanic, fixing and selling things on the market, and she's not afraid to defy her stepmother or tease her stepsister - even though she cannot leave because she could end up getting arrested for that, since she technically "belongs" to her stepmother. Then, of course, the handsome prince steps in, but there is so much more to this story than that. There's drama, there's mystery, and all in all it just sucked me in and didn't let me go again. 
 Of course there are some things that were slightly predictable. For example, (view spoiler)[ the fact that Cinder turns out to be the long-lost Lunar Princess Selene is something I think most readers could see coming from quite early on in the stories, given the fact that Selene is a key figure who supposedly died at a young age, but is rumoured to still be alive; whilst Cinder doesn't remember anything about her past. (hide spoiler)] Still, those small things aren't important in the big picture and besides, a little predictability never hurt anyone, especially since everything else was so unexpected. 
 Update: I just read the book for the second time and I went through it even more quickly this time around. I think the Lunar Chronicles might actually have surpassed the other series I really love (and there are a lot of them) and become my absolute favourite books. The writing style, the plot, the characters, the world-building - everything just fits together so perfectly, it's all extremely well done, and I don't want to put these books away. Ever.