The name Haldeman should be a familiar one to Sci-Fi literature fans: he wrote the widely regarded The Forever War. Winning the Hugo, Nebula and Locus awards (source), this book was as much about Vietnam as it was about SF, cleverly using the plot device of time dilation to illustrate the alienation of soldiers returning home from war.
Marsbound is a somewhat different book, and explores both early colonization of Mars, as well as "first contact." There is nothing original about the storyline, but Haldeman tells it well. It is from the first-person perspective of Carmen, daughter of two scientists that go with them to the Mars colony, along with her younger brother Card. And of course along the way she meets Martians.
When I first started reading this book, I almost thought it was a juvenile SF. The fact it was from the perspective of a teen-aged girl reinforced it. But as the character grew, so did the plotline. By the end it wasn't quite a juvenile I had thought it was. Furthermore, Haldeman's direct, basic, and uncluttered writing style kept it simple and at a good pace. I was easily able to read over 100pgs a night (I usually read for 2 hours) and the book came in at 304pgs, so it only took me a few days to plow through it.
There's some very interesting science-fictional concepts in it, such as the nature of the "Others" (only hinted at in this book) and of course the purpose of the Martians. Overall a good book, and I'm already reading the sequel Spacebound.