Dark Eldar can take so much anti-mech firepower in their lists, it is one of the most unique things about us. We are not short on it. At 105 points the ravager is a very efficient hunter on the tabletop. The problem is, anyone with any long range support is going to take it out. Facing 48" weaponry means night shields will not save you enough to matter. You are armour 11 and open topped. So technically an opposing anti-tank unit opens up fire, and there goes three of your lances. It is a very efficient target for your opponent to destroy.
You can deepstrike it or reserve it. However, if you have three lances you need them to do their job, and that is killing tanks. While killing tanks late game happens, you need to be able to get rid of high priority mechanized targets as early as possible, which clearly reduces the effectiveness of the Ravager put into reserve.
We are so loaded with anti-tank, and when list building if you concentrate on making sure your anti-tank weapons get maximized in your units, it can free you up to not only reserve your ravagers, but to change out their weaponry to Disintegrators. I mean there is nothing like moving 12" and firing 9 times at 36" with S5 AP2. With that 12" movement a ravager coming in from reserve can strike anywhere on the table and still tactically come in from an ideal location to limit incoming fire after it unleashes. Do this with 3 ravagers, and you have very surgical anti-troop killing machines that deny feel no pain, so they can handle shooting at heavily protected infantry.
I have been fielding both with lances and disintegrators now for quite a while, and also notice that if your opponent has tanks on the board, they are often not as concerned about a ravager with disintegrators, freeing it up to do its work. I have been amazed at how well my disintegrator ravagers have been doing on the tabletop and utilizing three of them from reserve, means pinpoint strikes, hopefully late game so they can do their best at key points on the field.
The Razorwing takes this tactic much further. Replace it's lances with disintegrators and upgrade you mounted rifle to a Splinter Cannon. Oh yea, you get 4 missiles. The missiles can all fire, so lets look at what we can drop if we come in from reserve for a surgical strike. 6 S5 AP2 shots, 6 S- AP5 poisoned (4+) shots, and 4 large blast templates S6 AP5. Everything can fire, and if you come in and launch everything (all the missles), that should destroy most units. Razorwing x3, and at some point late game, you should be able to wipe 3 units off the map as you come in. That to me is amazing.
Whether you use the Ravager or the Razorwing like this, 105 and 145 points respectively, you are dealing some late game damage when you need it and where. Using these vehicles like this can also warrant nightshields, since you are in so much control of where they are going to be, but that is only if you have the points.