I am currently using an eagle industries 3-point sling that works ok ... but I am getting ready to get one of the vickers tactical 2 point because of my sling getting in the way of the charging handle, and I have yet to find a 3 point sling that looks like it wont get in the way.
I am not a fan of the 3 point. It used to be all the rage but now as 2 points are getting better I would go with one of those. I am using the Vickers but I really liked the look of the new Magpul that came out at SHOT.
I purchased a 3 point for my M1A Bush Rifle and AR15 (attachments are the same) and never use it. I ended up with the Turner synthetic AWS 1907 type sling for the M1A and the standard military cotton sling for the AR15. The 3 point seems to get in the way of the rifle controls and it is bulky. It seems to be great in theory though. I guess if I had to stand guard all day with the rifle at the ready I would use it.
I've tried them all, Single, 2 point and 3 point slings. 2 point works better for me, Single is very good for certain situations. Also, I got about 2 bucks in my 2 point sling. I took the end that clips to the sling mount to a "Tack Shop" (Horse Eq.) had them stitch the clip or snap to the nylon and sew a loop on the other end for the 550 cord. Looks and feels like a 50 dollar sling, but it only cost $2.10.