Best places to sell silver Bullion (USA)?

I'm going to sell off quite a bit of bullion in order to fund a startup business. ASEs, 1 kilo Libertads, Canadian Moose/Panther, Johnson Matthey numbered 1 oz bars, etc. In your experience, who has paid you the most for your silver with no hassles in the transaction? How long did it take for you to receive payment?

Thanks!

Chris