Mineral loss is still faster.

Only if you are looking for insane precision. In my snake map I can sent multiple commands befer one cycle even finishes.

Pointing and clicking is pretty dang easy also...

If you're going to go all keyboard, the real winner is an EUD selection system. Unlike any other system, if you have it deselect the units when their selection is detected, the player can hold down the key for a repeated input (which makes things like flying a wraith by grid system much easier); it also requires only keypress to activate. Not to mention, you get all the controls in a line, which can be handy...

The main downside is that you have to patch your map along with Starcraft.

This way you can detect the mineral loss, so even units lined up in the queue get detected.