I also highly recommend you read through MM's reviews of slings (2 pages worth):
http://www.militarymorons.com/weapons/ar.slings.html
You have to ask your self a lot of different, objective and subjective questions regarding how your sling is going to be employed the majority of the time. Are you patrolling for long periods of time and want something comfortable? (2point sling) Do you plan on transitioning to your side-arm frequently? (1point sling) What method/s do you plan on attaching your sling to your weapon system? etc, etc. All these are factors in your final selection.
I personally do not recommend any bungee type slings. The bungee is designed to be part of the sling allowing for easier muzzle strikes. If you do decide to use a bungee, just be careful jumping over fences, etc. Bungees work both ways = bloody lips/chicklets
And if you don't want to spend any money - you can go the practical route and just use a two quart canteen strap. This is completely proficient as a sling and is the ultimate in practical.