AVOID PULL THROUGH SHARPENERS!!!!!
Most of the "high-tech" pull through sharpeners remove too much metal through extremely abrasive stones, can cause cosmetic damage, and can damage the edge itself & leave more of a utility edge than they do a razor edge (i.e., the knife isn't nearly as sharp as it can be.) Over time, this accelerates the speed a knife wears out, as well as how often one has to 'thin' the blade. If someone has higher end knives like a Konosuke or Takeda gyuto, then they don't want to use anything that will accelerate wear by removing more metal than necessary. Further, as higher end knives use very wear-resistant steels that are capable of holding extremely thin edges, they want to take advantage of these extremely thin edges to improve cutting efficiency.
For those not wanting to spend the $200+ on the EdgePro or WickedEdge, or learn how to use a benchstone to free-hand, I highly recommend the
Spyderco Sharpmaker. It is easy to use, extremely safe, will sharpen everything from knives to scissors to tweezers to lawnmower blades, and very easy on the knife itself. It is also able to repair severe damage and reprofile a blade. Further, by using more than one stone, you can choose whether you want to leave the knife with a utility edge or a scary sharp edge, and so you can match the edge to the steel (some steels do best with a toothier edge-like D2, where as others prefer a finely polished one-like M390.)
Here is an example of why you might want a very thin angle, where you would want the cutting edge to do the work instead of physical force, because physical force could damage the food or result in slipping.)