Firstly, the video game plays completely differently to the tabletop version so you can't take it as a genuine marker as to what the game is like.
Secondly, Dark Eldar have been updated as a race since Soul Storm was made, so while it is a decent representation of what they are like feel and backstory wise, its no-where near a reflection of what they are like on the table.
That said, its always a good idea to play an army you like the look of, and the 'fluff', or background story of. If you don't like your army, you never going to enjoy painting and playing with them as much as an army you can enthusiate about.
People will try to steer you towards an army thats easier to play for a beginer, as Dark Eldar can be tactically different to most other armies. On the table-top they're best described as something of a 'glass hammer'. Hard hitting, but fragile.
As said though, if your first instinct is 'Wow, I love the look and feel of the Dark Eldar', theres nothing wrong with going with them.