I disagree with my hunting partner here. For the ranged attack people and those that have pets, leveling alone or in very small groups may not be bad. For those knights/barbarian types that take a beating during every fight it is extremely slow. I find I kill 3-5 normals and then am forced to rest. At that rate it is about 500-1000xp for each run.
I had purchased one set of boosters and had just started testing them to see how they worked. With only 3 kills before I'm forced to rest, it just doesn't make sense anymore for me to use them. When in a large group I could go much longer and the kills came faster so more fun.
I will say that it has made hunting and being hunted much more commonplace.
CHARGE!!!!