I have the ones like Heather and they work for drawers if they are on the corner.
We have the magnet locks at work (I think thats what mag locks are?) and they are pretty good, fiddley and a PITA if you lose the magnet! But your can't forget to lock them, which is a huge bonus.

Have you thought about the internal latch ones that screw into place, and instead of opening with a magnet you open the cupboard a little and push it unlocks. They are cheaper and just as good. Jazz sometimes pulls on the cupboard door and they haven't once come off or even slipped. I don't think they'd break in a hurry.