Typical compound telescopes utilize combinations of lenses and mirrors to bring light to a focus. A popular example is the Schmidt-Cassegranian. It utilizes a primary mirror, a secondary mirror that directs light out of the bottom of the tube, and a special corrector plate or lens in from of the entire light path. The reason they're popular is because they're mass produced by a few companies, and come equipped with pretty cool features like automatic GOTO capability for thousands of objects, automatic tracking of the stars, and other advanced features. They are a little more expensive than a Newtonian reflector of the same aperture, but should be considerably less expensive than the same sized refractor.
Commercial fabrication gets sloppy too.
You can get a good instrument, however. It's just the majority of users have these complaints. Your Eyes Cheap Handy Easy to Use Limited in use Can be hampered by vision problems Definitely get a set of these. You can't do anything else without them. This is the best first investment if you need to learn the night sky, and want to find out your level of commitment.