And as expected, this just turned into a deek measuring contest. Before you all even think of it, mine is bigger!

Going back to the original question, which I think has been well answered by now. I personally prefer doing my long rides solo. There is a certain sense of satisfaction that you cannot get with group rides. Wind, hills, hardcore, etc. It doesn't matter because it is only you. Organized centuries and other rides can also be fun in their own way. But I find it that although I may ride much faster on average given I get to draft from other people plus you ride faster as it is when others push the pace a little, I do dislike having to keep up with other people's pace. Ultimately, it is your personal choice.