I ordered these brackets for a basement finish project. I didn't see any dimensions at the time with regards to 1/2" or 5/8" drywall thickness. They work just fine with 1/2" gypsum. If you go to Lowe's and try to buy a low voltage box, last I checked they're about $1.50.
PROS: Cheap, just what the doctor ordered.
CONS: Being low voltage boxes, they aren't very sturdy (none really are). I used a pneumatic palm nailer to nail these to the studs, which made very quick work of them. But this is nothing I would ding this product for.