time, money, peace of mind - you can only pick too.
if you want to maximize what you get for it ebay and usaudiomart.
if you want to get it over quick, Echo, Hawthorne or TMR
if you want to feel good, do your research for what it's worth, it spend the time to list it here or another forum, let an audio club members review it, find the best home for it.
Ebay takes 14% but you will get that much more. I prefer usaudiomart.
I tried to sell a few things through Echo, they are good for buyers. They offered about a third of ebay prices. TMR offers about 50-60%.
Some audio stores will put it on the shelf for you on consignment.