Best by what metric?
You can't beat a Norton tri stone system if you are expert at hand sharpening with whetstones.
But that's near 900 bucks these days and results are entirely skill dependent.
I have a vintage example of one, from the 50s. It's got to be a collector's item by now.
If you sharpen lawn mower blades, the best system is an angle grinder. For machete sharpening I use a 6x48 belt sander.
For my kitchen knives, I use a Makita planer blade sharpener which is a wet stone system. Follow it up with a quick strop on the buffer with green chrome polish, and the edge is utterly terrifying.
Some people use the Tormek, others, Sharpmaker, others, Lansky, others, something else.
Start by determining what your budget is and do you want a powered system or a manual system?
What blade size and types will you be sharpening? How sharp do you need to get them to?