Here's my quick and dirty version for you. Notice that I am only reviewing gear I have used, or have talked with others about who have used the gear.
First of all, print off Joe's sharpening FAQ from this website and keep a copy in the bathroom- read it often! Also, I'd recommend Leonard Lee's sharpening book, even for just the pictures alone.
Sharpmaker: easy to set-up, fast, have 2 angle settings, portable. Best for setting/maintaining the very edge, not good at reprofiling. Can round off points if you are careless, can do plain and serrated blades.
Razor Edge Systems: stones cut quickly, guides work well once set-up, folding steel is genious! Takes more time to set-up, little angle choice, eventually you have to replace the guides (though not really that often, and not for that much money). Trains you to free hand sharpen.
Gatco/Lansky: gives you angle choice, set-up is longer than a sharpmaker, but shorter than Razor Edge Systems. Can do plain and serrated edges. Hard to sharpen long blades.
Electric sharpeners: often you can't get the full length of the blade in the sharpener, usually removes way too much metal/leaves a rough edge. Very quick though.
Belt sander and buffer: fastest method, can do flat and convex edges. Can't do serrations. If you like the edges on factory/custom pieces, this is how they sharpen their blades, for the most part! More expensive set-up, can quickly ruin a knife if you are careless. It doesn't take long to learn how to sharpen a knife though, and the versatility is awesome (axe, kitchen knife, pocket folder, lawn mower blade, and so on!).
Scary Sharp Method: this si sandpaper backed on a hard material, or on a mousepad for convex edges. This is cheap, can easily play with different grits, paper is readily available. Cons: if you aren't convex edging, it isn't any different than freehand sharpening! Note though that you could purchase a Rozor Ede Systems guide and use sandpaper as a hone.
Best sharpening system- belt sander/bffer, with Sharpmaker for quick touchups and serrations
Best for beginners? Sharpmaker, and the largest coarse hone you can find- coarse hone for reprofiling/thinning out bevels, sharpmaker for setting edges. Best inexpensive setup? sandpaper with Razor Edge Systems guide.