I don't like deep bracket boxes, I feel like they're flimsy. If I want a deeper box I use a deep 4 X 4 and mount it onto the wood stud by drilling 3 or 4 holes and using deck screws. I'll also usually knock out a 1/2" knockout and screw a fender washer in it's place.
There, I've confessed. I feel SO much better. I don't know if it's code compliant, but you'd have a hard time pulling it off with a crow bar.
Dave
P.S. I also mount my receptacles horizontally, so the deck screws aren't close to live screws.
