For selling, it's Craigslist (with cash ad carry exchange at my local police station), trade in, or nothing for me. People are conditioned by "free shipping" to count shipping as part of the price. I can charge much less on a cash sale and come out ahead over packing and shipping (time, materials, and cost), Reverb fee, and PayPal fee. And the sale is completely over at that point. No surprise from PayPal months later. I will occasionally buy on Reverb, but usually from dealers who chose not to build their own commerce websites.
The current model for online buying and selling is not that old, and may not have staying power. I would not have advised Servco to make this deal.