Saturday runs with the group have been nice I will admit. It definitely keeps me motivated (what else could get me to wake up at 5AM on a Saturday). Conversation helps keep the boredom of the long runs at bay and helps to make the time go by.
But there is also something to be said for getting out on the road alone. Some of my favorite runs have been by myself. Without any distractions it is easier to get in to a zen-like trance where the running keeps my mind focused on the rythym and cadence of my footfalls.
So I guess the debate about which is better will go on. Either way it's fun.