I just googled that camera. I couldn't find it's specs, but I'm highly inclined to believe it's native 4:3. So, if that's the case, you'll lose the same amount of resolution, either way, camera or post, doesn't matter.
chilipie brings up a good point. If you do it in post, you have greater control. Let's say you get a shot in which you accidentally cut somebody's head off. Well, if you shot in 16:9, that's it, that's what you got. But if you shot in 4:3, you have room to move the image up or down, before cropping.
So, there is an advantage to doing it in post. But as I mentioned earlier, the downside is that it can really be a time-consuming pain in the ass (and not all software crops as easily as you'd like to hope), because not only are you talking about cropping, but using footage that was shot in a resolution different from what your resolution setting is, in your editing project. Some software makes this a non-issue; some software makes it very difficult to work with.