>Racing>Training solo vs. in a group
Others have already mentioned some of the pros and cons.
One advantage that I enjoy is that when I run with these guys
Pedestrians get themselves and their dogs and leashes out of the way a lot faster.
It's a 5k. It hurt like hell...then I tried to pick it up. The end.
Both. I love group runs in the mountains and have several local friends I run regularly with. Most daily runs are solo. Some long runs in the mountains are solo. I do tend to avoid shorter, local group runs when I need an easy or recovery run because I tend to run too fast with some groups (aka the young, fast kids).