Let's see if we can add some information here.
The close-up rings are cheap and quick to do some close-up work giving close to macro (1:1) reproduction. They suffer from severe chromatic abberation and distortion, especially as you move off the center of the frame. Canon branded and high quality close-up lenses are much better, but still the worst aproach.
It is possible to buy closeup lenses that are corrected for chromatic aberration. They are two element lenses and cost less than $100. We call them achromatic closeup lenses because they are color corrected. Canon and others have these available and they work quite well - for me they work better than extension rings or anything other than a macro lens. I use one with my macro lens from time to time with excellent results. I agree that the single element ones are poor performers. Achromats have an additional advantage of causing no light loss, unlike any other of the options (including the macro lens.)
Another side effect of close-up lenses is that they shift the focus distance very close to the lens. The stores advertise this fact as great, however it is not. Working distance is reduced and so is comfort.
As does any close focusing device, including macro lenses. Working distance is a function of focal length. Reproduction ratio is a function of focal point.
Extension rings are added between the lens and the camera, and they shift the minimum focus distance closer to the lens while at the same time increasing the magnification. Since there is no glass, optical quality is not reduced. Actually it is "enhanced" as the working area of the lens is the center part of it, where all lenses (even cheap ones) perform best. The amount of light entering the camera is reduced as the extension length is increased, which is not an issue for metering (it's handled by the camer) but the viewfinder gets darker.
Extension rings don't increase magnification. They simply move the lens away from the camera body so that it will focus closer but no longer focus at infinity. There is no "enhancement" of any kind. They extend the entire lens, not just the central part of it.
A reverse mount adapter for the lens creates a magnification lens. Magnification is very high (compared with the normal orientation of the lens) however if you reverse mount a mediocre lens, the results will be inadequate.
It creates nothing. It simply turns the lens around around backward so that it will focus closely but no longer at infinity. In my experience this is the most difficult kind of device to use because there is very little working distance. Also the resulting reversed lens is very slow in comparison to the same lens right side out because the smaller rear element becomes the front element. Mediocrity in a lens is no different in either forward or reverse. I put it at the bottom of the list. On the plus side it is possible to get reproduction ratios above 1:1 depending on the focal length of the lens.
There are other combinations there, like mounting two lenses facing each other with one (telephoto) on the camera and a reverse mounted one (wide-angle) in the front. These combinations are fun (provided you have all the required rings, converters and a lot of patience).
......and don't care about image quality.
Macro lenses have a very important feature known as flatness of field. When you are working up close, the difference in focus between the center and edges of the frame is very noticeable. Depth of field can improve things but only to a degree. Macro lenses suffer from some of this as well because the primary lens elements in every lens are spherical. However, the effect is less pronounced than it is with a standard lens. While macro lenses do not perform quite as well as standard lenses at infinity they perform very much better up close thanks to a flatter field.
Personally, I recommend against lens reversing devices and extension rings. The former are fussy to use and the latter bring out the worst in the lenses that are normally used with them. Small extension rings used with macro lenses work very well. Large ones used with standard zoom lenses work pretty badly - to be fair, I'll just say they don't work as well as achromats.
If you can't spring for a macro lens, which would be the best option, then go buy an achromatic closeup lens and amaze yourself with how effectively they work. If you plan to buy a macro lens in the future, then buy an achromat in the same filter size so you can use the two together.
I use achromatic closeup lenses with medium format. I've done catalog covers and magazine spreads with them.