I have managed 480,000 miles on my original ball bearings. I don't think there is anything wrong with their design however I have a set of roller bearings to fit my car and I figured if my originals ever wore out I would change them.
As long as you know which type you have and adjust them properly they are both excellent. Design wise the roller bearings should be more efficient. It's up to you you pays your money and makes your choice. Just make sure to adjust them properly.
