technecly, i think that the equipment falls off, as you gain control of the creature not the equipment
The equipment stays attached to the creature, but you don't control it. That means: a) You can't play the Equip ability to move it. b) You can't sacrifice it to anything.
Rhadamanthus is right. The permanent you gain control of is the creature, not the equipment. The equipment has the ability to attach itself to creatures, creatures don't attach equipment to themselves (except maybe for things like Brass Squire ). If you cast Metallic Mastery on an equipment, you could reattach it, sacrifice it etc.
Ahh cool thanx came up in a draft last friday wasn't sure on how to play it, also with metallic mastery could i keep the equipment permanently if i attach it to my creatures? and what if its attached to something already?
At the end of the turn, the equipment will still be attached to your creature even though you've lost control of the equipment, just like how the equipment is still attached to your opponent's creature when you steal it. When your opponent gets it back, of course, first step is to re-equip to one of their own creatures.