Many of us have been to Autotrader.com, Craigslist, Ebay, Cars.com etc.... what's your take on these sites?

Are they worth listing your car or finding your next car? What do you like about these sites, and what are they missing?

I'm just curious because I feel like they either cater to dealerships or in the case of craigslist it's whatever goes up there and not easy to search and find what you may be looking for.

Thoughts?