Not at all like the book, but... Let me start by saying that the original novel by Robert A. Heinlein is one of my favorite books. The original 1958 novel, Starship Troopers, is a classic of the genre, with great action, good plot, memorable characters, and enough political and technical ideas to satisfy any Poly-Sci or engineering enthusiast. The movie...has great action.
Admittedly, a book that is really primarily about political theory and the philosophy of warfare does not make for a good Effects-laden sci-fi shoot-em-up, so I am willing to cut this movie some slack. The acting by the cast (mostly former Melrose Place or 90210 stars) is atrocious, the dialogue hokey, and the plot paper-thin. However, if what you are looking for is a lot of explosions, some good-looking people, and a lot of effects and gore, this is probably a good bet.
On the other hand, when you look a little deeper, the film does improve in my estimation. Director Paul Verhoeven consciously was imitating WW2-era propaganda films like "They Were Expendable", and he does a creditable job of that. In Verhoeven's previous effort to make a special effects spectacular out of an idea-laden sci-fi book, "Total Recall", he also stuck only loosely to the book, but he actually came up with a better story. In the case of "Starship Troopers", he wasn't so lucky.
Verhoeven grew up in Nazi-occupied Holland in WW2, so of course he tried to make a statement about Fascist military governments. What exactly that statement IS, however, is not very clear. One minute, we are seeing some of the "excesses" of the regime (voting rights limited to veterans, swift and harsh justice, a culture of violence), the next we are shown Neil Patrick Harris (Doogie Howser, M.D.) in a Nazi-like uniform and told he is a good guy.
My recommendation: Read the book. The movie is enjoyable, but the book is SO much better...