I have sold several basses via BassDirect and got the same price after comissions as I would have got on here with people trying to haggle the price down.
I sold a Peavey T-40 for £500, Yamaha TRB4 for £550 and Line6 Variax for £500 which I'd say was over the odds for every one. However, I didn't have to take photos, record a demo, manage the transaction, package it or worry about insurance and couriers.
By the end of the deals, BassDirect had their 20%, and I had a hassle free amount of cash about the same as i'd have had on here.