Metco. After dealing with Billetflows awesome customer service I can't ever recommend to anyone that they spend money there lol. So if you go BF go used.
FWIW I have one Metco single bearing idler and one Metco double bearing, the single bearing I've had to replace a few times, the double bearings have yet to need replacing.
I just mounted up my double bearing Billet Pro Shop idlers tonight. Seem like solid pieces. I compared it to a single bearing BF i had laying around and the BPS def spin smoother and longer.