The OXO is decent but the blades are time-consuming to clean, so I don't haul mine out unless I'm chopping up several types of veggies at once. I don't like a power chopper for onions if I want them to remain relatively dry; power choppers turn minced onion into a pulpy mess.
What I would suggest is a good all-steel high-carbon stainless curved-edge French or German Chef 10" knife, a largish cutting board, and a box of wooden matches.
To use a 10" Chef knife to chop efficiently, the trick is to put the fingers of your other hand flat on top of the blunt tip of the blade and rock it back and forth on the cutting board; chops fine really quickly that way. The matches are to prevent eye irritation; just stick the clean end of an unlit wooden match between your teeth like a cigarette while you chop, and there is magically no eye irritation. To get the onion smell off hands, wash the stainless steel knife in soapy water, being sure to run your hands up and down the tang of the handle with soap; rubbing wet stainless removes onion and garlic juice and leaves zero odor behind.
Here's a secret: Americans don't tend to love 10 or 12" knives, so you often can find good brands on closeout because they don't sell that well. I've got a very good Henckels knife that I got on closeout for $22 a few years ago. (I like German and French makes for a knife this style because they have a large curve to the blade, which makes them easy to rock. Japanese knives tend to be straighter.)
