Pull-through sharpeners won't do anything for your blades other than keep them fairly blunt - in fact, as an ex-chef I can say that every knife I've ever seen sharpened on a pull through was blunter than the worst sharpening effort of first-timers on whetstones, wetstones or even drystones. Pull-through sharpening gives a 50/50 bevel, and many knives are sharpened for handedness either to single bevel or 30/70 (right-handed). Less commonly found are 20/80 etc (and 80/20, 70/30), while no-one really bothers with 60/40 as it's not worth losing the benefits of an ambidextrous knife for what amounts to very little benefit for someone who prefers a handed knife (ie. won't buy it anyway).
If you care at all for your knives, sharpen them using stones. It's more effort to keep up a truly sharp blade, but there's a lot of metal on a knife to lose over time.
Remember: always practise sharpening your best knives last - practise creating an edge in soft steel, maintaining an edge in medium steel and then and only then, refining a blad of hard (high-carbon) steel.
PS. Through-pulling on a HC knife is likely to blunt the rollers/plates and/or chip the knife from shearing forces. It's a bad idea if you have anything at all from JapaneseChefsKnives (JCK) or their other knife shop to take it anywhere near a through-pull. Put it in the bin and sit down with your mom to watch lessons on sharpening from youtube/vimeo.
Didn't intend to write this much - got all up in arms :/
thanks, i never got me a Pullthru since i hear that MOST pullthru's really Shave off more metal with the Carbide side than the course side of a stone.
I always had a Whetstone thats REALLY old, my Mom told me to use it so i did.
Took a bit of awhile till i got the hang of it.
I pretty much Semi-Mastered the Stone sharpener
i always sharpen my family's knives, since i heard they usually go to my uncle who uses his Electric Sharpener
they had a stone in a higer grit than mine, and My results were better! :)