It's just not as straight forward as some would have you believe. Without enough aperture, there are many wonderful deep sky objects you simply can't see. Because of this, I generally encourage all beginners to start with as much aperture as they can manage, and that will almost always steer them toward a reflector. However, I believe that such esthetics will be only truly appreciated by the more experienced viewer. I find this to be much more subjective when comparing optics.
More contrast is better .
First, and foremost, there is the central obstruction. This doesn't have nearly as much effect on the total light being gathered as you might expect, but it does decrease contrast and also to some degree, the resolution. Because of this, a refractor will be superior to a reflector of the same aperture . Your milage will vary, and it's easy to make claims when there isn't a standard metric for measuring constrast. My own experience has been that the Takahashi refractors have better contrast than most refractors of the same size, and certainly any reflector.