Well here goes my 2 cents worth, right or wrong.
I would prefer some degree of quartering away every time. I hunt from elevated stands and the only time I would prefer a little less quartering shot is if the deer is fairly close in and the shot angle is steep. If you study the vitals of a deer closely, and think about what an arrow would penetrate at different degrees of quartering angle, you will find that the quartering shot actually gives the widest margin for error. It is very difficult to get only 1 lung with a quartering shot. It is possible, but most likely you get both lungs because they are so close together on a deer (whole different ballgame on elk or moose or other big animals). As Shawn mentioned, you are also more than likely going to take out the diaphragm which in itself can be a killing shot. Also, just as the shoulder covers vitals on a quartering towards shot, it uncovers vitals quartering away. Much of the vitals are actually between the shoulders. On a deer that is quarterering at 45% you have about a 12" wide kill zone that guarantees the diaphragm, both lungs, and likely may include the liver or heart. One other thing I've noticed on deer that I have killed quartering away (where the arrow penetrated behind the ribs) is that they all reacted more like a gutshot deer. They jumped and then walked off slowly. They either went down in sight or were wobbling badly when they went out of sight. It sure looks good to me when they turn slightly away and get the shoulder out of the equation. Anyway, thats my thoughts on it, but I would be tickled to death with a 12 yard broadside shot tommorrow (opening day in AL) as well.