While I was at Rick Welch's shooting school a few weeks ago I had the same question. Rick had fletched up a GT Exped. hunter 55/75 for me to shoot. We shot a GT Trad. 55/75, identically fletched, both with 125 grain field points, one right after the other.
I would not have believed it myself, but the expedition hunter arrow was noticeably faster, and the trajectory was flatter. The traditional arrow consistently hit lower than the other.
When we shot them through the chronograph I was shocked, as the traditional arrow came in at 178 fps, and the expedition hunter came in at 190 fps. I didn't think that it would make that much difference.
Just for reference, the bow was a 62" MOAB, 48@30". I was drawing between 30.5" and 31".
I'm not into all the fps, foc, blah, blah, but you could really see the difference.