I think to get accurate results you'd need to test more than 10 well trained people.
I think a mix of both over time is best, when you think of the ratio of twitch fibers determines force x time and that ratios of slow and fast twitch vary throughout the body and from one person to the next.
for example, Tests done had noted that very strong people that lose strength quite quickly which would indicate that heavy weight and low rep would be the best way to train