The few occasions I have raced my 320 against old style longboards, I have been doing as well or better upwind than the long boards but not so well downwind. Some of that could be a differnce in skill since the others were much more experienced sailers.
I certainly find it easier to sail the 320 downwind (stability) because of the wider more boyant tail. I am only 64kg, so I imagine a heavier sailer would also benefit from the higher volume of the longer board.
I think the 320 could barely be called a hybrid although it may comply with hybrid class rules. compared to the previous SB hybrid race and SB hybrid formula, The RSX, the Bic Hybrid. It is much closer to a lower volume raceboard than any of the previous hybrid designs. The 2010 phantom 320 detail is even closer to the 380 than the previous model shown in the video.
I think a skilled light person on the 320 would give the longer boards something to think about, but it would always be hard to beat the longer water line in light winds.