The Sparrow does a really good job of drawing characters and describing their interactions, with people of different backgrounds and classes interacting. It includes interesting explorations of religion and faith. Several of the main characters are Jesuit priests, others are agnostics, and it is refreshing to read a book where religious and non- or differently-religious people work together and get along, instead of being depicted as fundamentally opposed.
However, I think Christians would get more out of this book than I do —as a buddhist/agnostic, I didn't find myself getting emotionally involved when the characters discussed whether God exists and how/whether God intervenes in the universe directly and if God is good and omnipotent then why does God allow evil to happen.
The Sparrow won the Tiptree award for books that explore gender. On the one hand, I am not especially impressed by the gender exploration per se. (In one of the alien species they encounter, the females are larger and in charge of things, and the males are smaller and take care of the young. So, the roles are just reversed. So what?) But the main male protagonist is a rape victim, and this also touches on gender, since in my culture it is assumed that rape is something that happens to females, thus male rape victims are considered "feminized." I appreciate that this book approaches the topic of male rape victims and does so seriously.
I also like the explorations of celibacy and love expressed in non-sexual and sometimes non-spoken terms.
This is one of a type of novel that gets a lot of its energy by hinting "There is a horrific secret to be revealed!" In this case you know some of the facts early on but you don't know why things happened the way they did. I tend to feel disappointed by such books because I'm not shocked by the revelations the way the characters are.
OK, that was the well-behaved review. In my private journal entry, the way I commented on the "horrific secret" was this...which contains major spoilers for this book and The Devil of Nanking by Mo Hayder, so it's in rot-13:
V erpragyl ernq "Gur Qrivy bs Anaxvat," juvpu vf nyfb n obbx nobhg n ubeevsvp frperg. Ng gur raq bs guvf obbx V sbhaq zlfrys fnlvat "Qb lbh UNIR gb unir onol-rngvat, puvyq-xvyyvat, encr/gbegher, naq cebfgvghgvba va n obbx gurfr qnlf?"
There were lots of opportunities for "suspension of disbelief issues" in this book. Mostly they didn't particularly bother me, with one exception: I can't believe that humans a few decades from now would send highly qualified social anthropologists into space to whom it would not occur that (more rot-13) vagebqhpvat ntevphygher gb n uhagre-tngurere fbpvrgl would cause major changes and problems in that society.