Are you asking about calipers vs canti's? Calipers can be center- or side-pull. Canti's can be center or direct pull. If you are talking canti's, I second the recommendation if you're going to do even lightly loaded touring. They have more power and are the preference on tandems because of this. A loaded single bike can have similar stopping challenges. Squeal should not be a problem if they're properly setup. Just stick a very thin piece of card board or a folded 3x5 under the back end when you set them up. Cable adjusters can make all the difference. If the levers themselves don't have a cable adjuster, you can buy an in-line adjuster that goes on the cable.

As always, Sheldon covers it well:
http://www.sheldonbrown.com/canti-trad.html

I just setup a Kelly cross bike with Avids and some old Real Designs levers and I love the combo. Hubby set up his Knobby X with Dia Compe Levers, in-line adjusters, and XTR V-brakes. His setup will stop you on a dime. The problem is your nose will be on the dime if you aren't careful.

When do we get to see pics?