A particular aspect which I liked was the level of tech-talk, the research was impeccable - JR Marlow certainly knows his stuff, best of all everything in Nano is plausible. The technology may seem a little far fetched at times but it really isn't. To my mind at least, everything is achieveable, maybe not now but sometime in the future.
The characters were interesting, you really get to know the lead male, John Marrek. I started to really feel for the man, as you will find out by reading.
The balance of tech/politics/ethical reasoning throughout ensured you were turning the pages late into the night. From the start the pace was set with an unexpeced event.
Overall; an entertaining read.