I picked up a tattered copy of Contact because I thoroughly enjoyed the 1997 movie with Jodie Foster. The characters were vivid with complex back stories, the plot itself was intriguing, and the interplay of religion and science was completely necessary.
I was not as impressed with Contact the book as I had been with Contact the movie. Although the plot was the same, it is obvious that Sagan is a scientist, not a literary author. He writes in a style that has mass market appeal--a generous amount a plot, a little mystery, a little self awareness and characters to hold it all together as opposed to everything else holding up the characters.
The science he uses feels like a side note: not particularly an explanation, but just white noise. Similarly, the characters don't evoke the same emotional reactions as the one from the film. They dont' appear to have feelings to emotional experiences, and Jodie Foster's character in the film feels more real than Ellie.
There were moments that didn't make as much sense in the book (the use of 5 in the machine as opposed to just 1). Because there was such a large number of individuals in the book, the fact that their experiences were ignored completely didn't sit as well as the one lone uncorroborated story in the movie.
Yet the feeling in the last 20 pages of Contact was what I was really searching for in the entire book. The spiritual realization, the perfection of the universe, and the message in mathematics was absolutely a perfect end to the story. It is an ending that sits well with religious individuals and skeptics, but it sits particularly well with people on the cusp with diest or pantheist sentiments.