Quoted:
Watch the video and check out how the sling is used
AK shooting
That video shows why I dislike 2 point slings
They only really work in a combat situation if you only hang it over your neck. This becomes very tiresome and uncomfortable over time.
I prefer slings to go over my shoulder and around my back. Much more comfortable for long term use. For a two point to work like this, it has to be very loose which makes it leave the rifle hanging very low when it is hanging from the sling (like during a sidearm transition).
I like one point slings because they go around my back, allow the weapon to hang high, and if you get one that has a bit on bungee cord to it, you can make it hang very close to your body and still be able to shoulder it.
I'm basing my sling preference on being an infantryman in the Army for 5 years(patrolling for hours at a time, roadmarching, moving across the drop zone, etc). So someone who just wants a sling for simple range use or short matches will have difference needs and preferences.