While RJB's do get drugs, they are considerably over costed for what they get. As previously said, everyone and their brother gets turbo boost for free, along with being cheaper options in 4th ed.
By that quota, RJB's are very overcosted.
For less than 25 points each, they should be able to have drugs, hit & run and eldar jetbikes if they remain an
FA choice. Possibly even an extra attack for the spiky bits, like chaos has.
Lets compare eldar jetbikes to one another. (Minus equals disadvantage, plus means advantage, equal sign means equal)
Eldar Jetbike: 
can turboboost (like all bikes now)
+ (because they dont pay for this ability)
increased toughness (like all bikes)
=
cheaper
base cost
+
BS of 3 -
STR of 3 -
3+ save
+ has eldar jet bike rule
+ can upgrade 1/3 bikes to have shuricannon - (While Eldar can get more weapons in the squad, I feel
DE have the advantage because of not being contingent on squad numbers for number of weapons)
str 4 guns
+
has twin linked guns +
AP 5 =
Range of 12" -
Assault 2 +
cheaper character, who is potentially more effective with free upgrades and cheap upgrades +
character can use psychic abilities
+
character has access to a lesser number of upgrades
-
can take a warlock on a jetbike in the squad
+ Reaver Jetbike:

can turboboost (like all bikes now) - (because they do have to pay for this)
increased toughness (like all bikes now) =
more expensive base cost -
increased
str to 4
+
BS of 4
+ 4+ save
- str 3 guns
-
AP5 =
does not have twin linked weapons
-
range of 24 inches +
Rapid fire -
can upgrade two weapons in squad to two different weapons, no matter how many models
+ (I feel
DE have the advantage here)
more expensive character who is potentially less effective with more expensive upgrades. -
character cannot use psychic abilities. -
character has access to a greater number of upgrades +
combat drugs +
Taking all the pluses and minuses and averaging them we have:
Eldar bonuses = 5
Dark eldar bonuses = -2
It is apparent to me that even though the
DE do have nice bonuses, it is clearly overcosted when in direct comparison to their closest kin whom I feel it is quite fair to compare them to.