Dicing onions - what do you do, and why?

Ron, it really depends on 1. your comfort level, and, 2. whether or not you care if the dice is more or less the same size.

The way most pros do it:

Slice the onion in half, the long way. Trim the blossom end, but leave the root end attached. Peel the halves.

With the flat down on your board, make one or two slices (depending on size of onion) from front to root, without cutting through the root end.
Then make a series of vertical cuts, front to back, again without cutting through the root.

Then, using the claw-grip technique, slice the onion.

Result: A dice of whatever size you want, with most of the pieces similar in size.

All of this is a lot less complex than it sounds, and only takes a few more seconds than if your were slicing the onions into half moons.

Tas,

    Tas, can you add another selection to your poll?

•     Like Brook does it  (CHECK)
  

Ron, quality can be defined as "how well do they take an edge, and how long does it last." The point being, the knife should be sharp to begin with.

Some confusion, too, stems from the fact your subject says "dice," but you seem to actually be talking about slicing. So, which did you actually have in mind?

i've tried the way with leaving on the root and never have much luck,

Notice that I listed "comfort level" before anything else. With all knife work, that's the first, and most important, criteria. Assuming it is sharp, the knife should be an extension of your hand, not something you are fighting. In short, you use whatever technique works best for you.

And, did I mention, your knife has to be sharp?