I prefer to hone freehand on benchstones (DMT diamond hones). An angle guide can be useful -- I use an old Buck one -- as it helps to create a consistent edge angle. There is no magic to sharpening and there are lots of books on the topic.
I sharpen free hand too. In addition to an EP Pro I also have a set of Norton (and various other) stones, various lapping compounds & plates, a bench strop with loaded leather strops, a 1x42" belt sander with belts in logical increments from 80 grit down to 9 micron and leather belts loaded down to .5 micron + and unloaded hard belt for power stropping. I have a set of Shapton Glass stones and a DMT X Coarse plate on the way. I also have 5 bench grinders and polishers and a 6x48" belt sander but don't use them for sharpening.
I agree there is no magic to sharpening. I like the freedom of using bench stones too. However, in most cases the more accurate the edge angle is held the better the result. I guess I am a knife nut and like to have more then just a working sharp blade. In many cases I like to show off a bit, and feed my ego. I like to get knives as sharp as possible and looking good (polished). I see you like using a guide for an accurate edge as well.
I am not good enough yet to get the same results from free hand as with the EP. Still, freehand I get very sharp blades that work well and most folks would be happy with, some cut themselves on because they have never had a knife that sharp, etc, but I want more. The EP is easier to get those kind of results on and it is done very fast. It is the fastest system I have used other then a belt grinder. It takes lots of concentration for me to get even close freehand to what the EP can do even when operated by a novice. On the EP I can keep a very precise angle and repeat it again when changing from coarser to finer and finer stones until polished. One minor slip, freehand, to a more obtuse edge angle and I feel I have ruined what I have been working on and need to back up. If it is not too big an angle change it probably doesn't matter much, still cuts well, and just becomes more of a convex edge. But, I don't like it and many can't hold an accurate angle, or pick one for that matter, as well as I can. Much of a slip and the edge really is ruined.
I have read that the Buck Guide is one of the best of all the little gadgets and guides. Better then the Lansky and Gatco and you get to use full size bench stones and direct the pressure on the knife to the stone. Unfortunately, I understand they don't make the Buck guide anymore. The DMT looks like it might come the closest to the Buck of all the currently available guides when used with Bench Stones instead of the little DMT plates.
Do you have and pictures of the Buck guide? How old is it?
I like the EdgePro for its precision, and speed. It is also easier to get a good job then with bench stones (freehand) IMO. I sharpen freehand and prefer it for some blades. I also can't always pack an Edgepro. It is easy to carry a few bench stones. IMO, with an EP a beginner with some mechanical aptitude and a vision of what a sharp knife is (a plan) can get results equal to a professional with only a few hours of experience. It might take years to get to that level freehand. A guide might speed up the process though.
I enjoy sharpening so I compete with my Edgepro and try to be that good freehand and with a belt sander (which is easier by the way).