We have always used Portsmouth ratings in OCRA with excellent results. We have had many different classes of boats racing and it is proven accurate except for boats that do not get sailed often in areas that report their race results. That is why it is so important that every regatta report results to Darlene Hobock. The more experience a class has in Portsmouth, the better the system rates it based on actual finishes.
That's why I believe a measurement system is better. Rate the boat, not the racers.