I'm guessing that "anti-choice" is clear, so I'll address the other one.
The pro-choice crowd is highly disingenuous on several fronts. One of them was addressed above: the ethical considerations are not as cut-and-dried as they make it out. (Gender selection abortion being a perfect corner case that will cut you if you ignore it.)
In addition, however, they overlook that a lot of abortions are the result of raw desperation. People simple can't afford to have the child, say. There's plenty of studies that show the unhealthy psychological effects having an abortion can sometimes have (not to mention that it isn't a physically neutral procedure either!), but this is glossed over in the rush to label it "a choice" as if it were the same as choosing which candy bar to buy in a corner store.
I suspect for the people who are damaged long-term by the trauma of having an abortion that better options exist if the people so all-fired interested in "choice" were interested in actual choices instead of focusing narrowly on abortion. For instance the large number of middle-class, white, suburban women who are "pro-choice" don't seem to be doing anything to provide, say, a support network for women who want to make the choice to keep the child but for pecuniary (or other) circumstances which intervene. Because, of course, such a support network is a long-term commitment of time, money, and actual human relationships. It's far easier to just scream about abortion rights; it takes a lot less out of you.
Given the realities on the ground, however, I lean more to the anti-life crowd than I do the anti-choice. I support them while holding my nose.