xGrab records your screen actions into a movie. It compresses the movie as it goes so there's need to post-process the captured frames. This means that as soon as you stop recording, your movie is ready to play.
xGrab captures your entire screen. That's it. No bells no whistles. But its list of features will expand over time. Later in the development cycle, you'll be able to select a capture region, crop or scale the captured video to a smaller size, just like most other thrice as expensive capture applications.