i ride bikes with both brake systems and the cantis are most definetly more 'powerful' against the rim.

the modern, industry wide "dropless" straddle cable design is a result of a lawsuit; Shimano BR-R550s or other cantis that come equipped with a "dropless" straddle cable can be retrofitted with traditional straddle cables- very handy if you have a coupled touring bike.

see my other comments about LR brakes in your crosspost in the Commuting forum.