Personally I've found a huge difference in planing AND pointing abilities between large freerides and formula boards. I plan in 6-7knots on a Formula 156 with 70cm Drake fin and Ezzy Infinity 9.5m at 62kgs. The thing is with a large freerider you'll find it difficult to point high in limit-planing-wind, and you definitely be battling to stay up wind. With a formula, you'll bear off to gain speed, then be able to point and sustain planing even pointing really high. That's definitely a plus.
JP Super-X 106l, North F8 Ram: 5.8m,