Metal boxes? That's what I use! Both for customer service calls, as well as for rewiring my own house.
"Bracket boxes" dominate - standard depth 4-S boxes with the appropriate mud rings.
Correction: I use mud rings a bit deeper than I need, and set the boxes back to compensate. You'll want to make a spacer to help you set the boxes to the right depth. This practice means the drywall guy won't be fighting the screws on the face of the box, and things won't get beat up nearly as much.
Checklist: Boxes. Bracket boxes come in cases of 25.
. Mud rings
. Green screws w/ pigtails
. Cable clamps (boxes of 100)
. Mounting screws (short drywall screws are fine)
For dryer and range receptacles you'll want to use the larger 4-11 boxes, deep style. You can use a separate bracket to mount these.
