you don't lose AF or aperture with a reversed lens. you mount a lens to the body, then you screw a lens 'backwards' onto the end of your lens. AF still works and aperture is still set as normal.
you can try this at home for no cost. just hold a lens backwards next to the lens you have mounted. you can use clingwrap and gaffer's tape to hold it without your hands.
the wider the reversed lens, the higher the magnification.
personally, i think the nicest true macro lens is the MP-E 65mm. it's easier to focus than using extension tubes, even though it's manual focus. it also has a tripod collar. it just needs a good light source.