I have an EdgePro, KME, Sharpmaker (x2), and some assorted pocket stones. My favorite for full bevel sharpening is the KME. For touch-ups on knives with with clean, even and accurate bevels, I keep a Sharpmaker out and ready. And on the odd occasion, I pull out the EP for very large blades, odd shaped knives, or complex grinds.
All systems have a learning curve (although some longer than others). All have their own set of pros/cons. Some have better materials, stones, tighter tolerances, etc. But with that, I think most all systems can be used to achieve better edges than many, if not most factory edges. Assuming the user is willing to learn the ins and outs of chosen system. Personally I think the best bang for the buck is the KME/Sharpmaker combo. If the person really wants to take on sharpening as a new skilllset. Unfortunately many people I speak with about sharpening, want to do it, but want it to work like an office copier. Put it in, then just press the green button. For those people I have no idea what would be "best".
IMO, most factory bevels are usually off enough (for my tastes anyway), that I want to reset the bevel. I'm a bit OCD about the bevel being even from end to end, and side to side. It also makes it MUCH easier to touch-up and keep sharp for a longer period. YMMV