This is the one book I have seen praised here endlessly. I am sincerely hoping it can stand with Neal Stephenson's work. I don't think there is any other author I can recommend unequivocally.
Three Body Problem is very thrilling to read; fast paced with a lot of cliff hangers, and excellent world building. The sci-fi/speculative bits are extrodinary, and although the characters can sometimes feel like their only role is to give a 'first person perspective' of the science, Liu can surprise you with the emotional depth that his characters exude.
The Dark Forest is in my opinion harder to get through than Three Body Problem, but the payoff is extraordinary. The pacing is slower with more world-building, and the perspective bounces around between a lot of characters without much forward movement. I had to put it down for a while and read some other books before I built up the motivation to finish it (it helped that I already bought the next book, so I felt guilty not finishing).
Deaths End, the third book, is unbelievably amazing. The pacing is more similar to Three Body Problem, and the science is astounding. All of the patience necessary for Dark Forest pays off because Liu is able to bring his world-elements into a mesmerizing display of action and conflict. I'm only half-way through and I've lost count of the number of times I've had to take pause and simply exclaim "Wow!".
Thanks, always looking for new stuff to read. (edit: not really new, but new to me :)
Concerning The Three-Body Problem, I found it a bit disappointing. Great build up with a rather traditional solution making some things of the build up looking a little bit silly.