They hold really well. I have thick hair (5" pony) and a 3" barrette will hold a half-up for me, and that's asking a lot. A French-back barrette will hold more hair, but for my hair at least they're too damaging so I won't wear them.
3a/b, fine, normal porosity, high density
Wash: CJ Daily Fix, As I Am, TJs TTT
LI: Suave TC + CJ CCCC, brushed through with Denman
Styling: Smooth in LAL Wet Look gel, scrunch, and plop 10 minutes, then add a little more gel, cover with silk cap, and sleep on it
Refresh: 3:1 water/Suave mix as needed