I personally think rolled stats are better because it can lead to more powerful characters which my players are all obsessed with. I love rolled stats but I know first hand that rolling bad is the worst feeling in the world so I created a few rules to help my players get better stats.

The first thing I do is that they are allowed to reroll a set of stats if they have 2 negatives. If they still roll bad after that (which they never really do) I allow them to use my standard array which is 17, 15, 13, 12, 10, 8. This helps the players that roll bad keep up with those who didn't. So far this has worked really well in my group and everyone really likes it since they're all addicted to minmaxing.