The views through a 200mm v 130mm and not comparable. The 200 will simply blow the smaller scope away. The mount supplied on the 130 will make it necessary for you to be an acrobat to get to the eyepiece many times, its always easy to view through the eyepiece of a dob. Setting up a dob is simply putting it on some realtively level ground, the GEM needs aligning and a lot more fiddling. The larger aperture will handle light pollution better as well.
Guess which scope gets my vote
