Definately stronger, and a bit heavier.
To put the weight in perspective, Profile cranks with a euro bb will add about a pound to your ride, that is if you had weenie-light cranks installed at first. Most people that freak out over the weight don't consider that the profile system includes the bb and spindle.
A set of euro bb profiles without the spider or rings weighs about 1100g.
A set of typical MTB crank arms with rings plus a BB weighs in about 900g.
Figure once you add a spider and rings to the profiles, it'll add a little under a pound to your bike.