I have owned several different sharpening systems and here are my inputs,
The Smith and Lanskey (clamp type) are excellent for small blades but don't work well with large knives and double edged blades.
The Spyderco sharpmaker works on anything but takes a bit of time, I use mine in front of the TV. If you
can count, this one is easy to use and works on pretty much anything. and is pretty flexible.
The Chefs choice is excellent for large kitchen knives and works well on thin blade knives, I use a model 120 and I have to warn my wife when I sharpen her knives! Thick Bowie blades may not fit in the slots. This takes a little bit of skill to use properly.
The most flexible is still the bench stone, you can sharpen anything from a chisel to a lawn mower blade but this is also the most difficult to use properly. I prefer the Diamond whetstones, pricy though.
Whatever system you use, PRACTICE!, try a knife you are not too attached to first and figure out the best way to use the sharpner before you go to town on that $300 custom.