I've had several bikes with Weinmann brakes. None were even close to the Campagnolo braking quality. I always attributed this to two things - the generally longer brake arms on the Weinmann (less stiff) and the eventual wear of the plastic pivot bushings and slop the results from the worn bushing (less stiff). Attempts to reduce the slop from a worn bushing will result in the brake pivots binding up and the pad rubs the rim.

That said, there's nothing wrong with Weinmanns. They're different (more spongy) than Campagnolo..

I agree the rear brake cable hanger will be out of place with side pulls but you'll get used to it. Whatever you do, do not cut the hanger off.