a refractor uses a glass lens as the primary, where as a reflector uses a concave mirror as the primary bit that catched the light,
from what i can remember (anyone correct me if im wrong) to get the same images resolution/ quality a reflector needs to be roughly twice the size as a refractor. hence a 4" refractor is roughly the same as an 8" reflector, (ie has an 8 inch mirror).
hence a reflector tends to be housed in a fatter tube, but it does looks better in my opinion,.
the other thing is to look at the focal length of the primary lens, or mirror, this will give you and indication of X multiplication, its basically worked out as focal length of eyepiece/ focal length of lens or mirror. (ie: 10mm/1000mm will give a magnifiaction of 100 times or there abouts.)
your best bet is to go to a specialist camera/telescope shop where they will be able to explain a lot better.