Are counter top knife sharpeners like the IQ knife sharpener good for sharpening knives (or cheap knives)? I have used the IQ sharpener and it is still hard to cut through big onions. I would like to know if it's problem with my technique or the product category itself just sucks.
A pull-through sharpener will never do as thorough a job at sharpening your knife as a stone, and over time will lose its efficacy and actually dull your blade. In a pinch they can be useful, but be sure to give the knife a few passes on a good quality steel afterwards, as the pull-through sharpeners tend to remove metal quite coarsely.
Using a sharpening steel from new is probably the best method - but it takes some practice. You can find plenty of how-to on YouTube but my word of caution would be to ensure that the back of the knife is towards the handle of the steel (and consequently your hand) not the edge.
Sharpen every time you pick up a knife to use it, and then every time you clean and put it down. Just a few strokes in this regime will keep even less expensive knives sharp. Don't forget to wash or wipe off the residue on the blade before you actually use it. The steel will leave micro-sized filings on the blade and probably some dirt from itself. Wipe the blade carefully on a piece of paper towel to see what I mean!
As an aside I have Polish colleagues who sharpen one knife on another - scary stuff.