From my experience everyone has dealer.com so it may be generic. That being said, everyone has dealer.com so they must be doing something right.
We had dealerskins in our dealership 3 years ago and the GMs and owner hated it. Not exactly sure why.
We used Ecarlist as a website creator for the past year or two. The website was excellently designed, but tech support took forever. Trying to put up a weekend sale, forget about it unless you give them a two week notice.
Currently we're using Izmocars. Their tech support is in India but are very knowledgeable and good at design. Depends on if you can deal with that or not. They are building a new platform called "Indy" that will be released next month to current customers. I got a demo of it and it blew me away. It lets the customer basically change anything about the website. (I was skeptical as a computer guy when people promise stuff like that, but it's a spectacular web designing tool for laymen)
So Pros for Izmo: great designs, great SEO (Cobalt and Izmo have the two best SEO I've seen), vehicle selector is slick, back-end tool allows you to add specials instantly in numerous formats, new back-end tool will allow full website control and change.
Cons for Izmo: tech support is in India but working on Pacific time zone. Everything must be done by the book so nothing can be rushed. (both good and bad).