I enjoy both. I ride by myself for 3ish hours almost daily (both ring and trail work), and prefer being by myself or with my two closest friends. Group rides are okay, but I cannot handle them often. I usually have a cell phone, but where I ride is pretty much a dead zone for reception. Most of the time, someone knows I'm at the barn, and my boss sees my car when she gets home, so she would look for me if I was missing for too long. As far as self defense, I have carried a gun (.38 revolver) but don't carry regularly.
"But I can tell you this: When you get to square ten, all of square one will be in it." RayHunt