CL totally changes from area to area and then from dealer type to dealer type.
In WA we have areas like Bellinham where there is very-very little traffic (therefore no results) and heavy flagging, on the other hand in the Seattle metro area and surroundings CL will do twice the leads/traffic than Autotrader for about half the money.
About dealer type, in general most franchises do fine, but Cadillac has done great and on the other hand one of my VW dealers totally wasted its money.
I just checked Annapolis and on the 6th there are barelly 2 pages (a couple hundred cars) up. In Seattle you will have 4000 to 5000 going up in one hour during peak times. On the other hand, Washington DC has really good traffic.
If you are close/willing to post into- a high traffic area, and Jeff doesn't shut my posting, I will do a 2 week free for you to test it. I don't know that state and we can look at the numbers after 2 weeks (one week to load up ger ready and second week to see traffic).