Infinite

This is exactly the genre of science fiction that I like to read: using the future to explore themes of identity, consciousness, artificial intelligence, and the nature of reality. It wasn't as “deep” as some works in this vein (like those of Greg Egan), and sometimes the characters rushed too readily to conclusions which I thought warranted more investigation. But it was a page-turner, keeping me engaged all the way through with cliffhanger chapter-endings that repeatedly rushed from crazy scenario to new revelations.

I'd only caution that the opening chapters, in particular, are fairly gross, with unnecessarily-gory or fetid descriptions of the protagonist's unpleasant situation and the ways he has to cope with it. If you can get past those, you'll likely enjoy the rest.