I really don't favor one roller over the other, but rather always making it an outside roller. IE If I am left to right, I will roll right and turn left. I feel that this is the best way for me to present the Harrier Roll. I also prefer Right Rolling in very high speed looping maneuvers. They are more natural to me than to the left. I have really started to roll left a lot lately, trying to get both rolls the same. The hardest part is making them very axial. I will only roll to the direction that I think will best present the maneuver in an extremely axial fashion. Rolling to the inside is not as natural for me, but QuiQue did an amazing job with his opening maneuver last year during the Masters and the TAS. Check out his video as well on rocha-n-roll.com. Presentation is everything and making the maneuver precise is just as important. Hope this helps,
Mark