The Ravager is a BS4 F11 S11 R10 Fast, Skimmer, and Open Topped. It comes with Night Vision and Aerial Assault (can fire everything moving at cruising speed 12"). It has 3 Dark Lances and a menagerie of options. It's cheap. For the low point cost its hard to argue it's efficiency for the tabletop.
Being able to move 12" definitely protects you against assault (you can move out of the way, and 6's needed to hit). Where Ravagers will crumble is to a barrage of heavy weapon fire. Long Fangs, Hydras etc can very easily and quickly make short work of your heavy armored Ravager as well as pretty much any Dark Elder vehicle.
The Dark Lances may be freely exchanged for Disintegrators. I personally don't like this here, but if your lists design calls for it, I could possibly see it. If you are looking at this option, take a close look at the Razorwing. The Ravager gets the usual Flickerfield and Nightshield options as well.
Unlike either the Razorwing or the Voidraven, the Ravager gets a ton of vehicle upgrades that might make the Ravager your weapon of choice. Shock Prow, Torment Grenade Launchers, Enhanced Aethersails, Retrofire Jets, Chain Snares, Grisely Trophies, and Envemoned Blades gives you a great deal of flexibility to customize it's role. These upgrades are amazing low in their cost.
I can really see the Ravager fitting the roles Dark Eldar players are looking for on the tabletop. At the moment, it is not as sexy as our Jetfighters and Bombers, but none-the-less I will be using these on the tabletop. Three Ravagers quickly field for 315pts with very mobile 12" firing platform.
Grisly trophies on one, could very easily make sure that any backfield objectives don't go anywhere (leadership re-rolls within 12") while the Ravager lays down a hail of fire. They can deepstrike with retrofire jets, or if we take a special character, and fire everything when they appear. If you already have a very heavy Lance list, fielding a Ravager with 3 Disintegrators would give you 9 S5 AP2 shots.
Will I take the Ravager over the other more sexy heavy support choices? In some lists yes. I am very taken with the razorwing and voidraven, as are probably most Dark Eldar players, so I will probably be fielding these over ravagers for the first few months. (once I build them). The Ravager should however see a lot of action on the tabletop. It is quick, efficient, flexible, and can provide a hail of Dark Lance fire to support your army.