if you buy the battle force, more than likely your arse will get whipped the first couple (hundred
) times you play.
Your better bet would be to search for a good DE warrior deal, (like a kid trying to get rid of the DE he got in the boxed set, etc.) get two soid squads of warriors, and a good dark eldar lord.
well, whichever way you choose, just keep playing with the DE, even if you lose, and keep analyzing your battles to decide what to buy next. Believe me, if you know what you're doing, you'll whup your friends like nothing with the DE.
Good luck, man.