Problem is it would be hard to compare, I plan on getting two identical machines, running them side-by-side, and every 2 minutes asking each for their hashrate, then averaging it over a 6-hour period.
The primespersec measure is for fun only, it does not necessarily reflect true mining performance. The only accurate measure is block rate, that is, given a fixed difficulty how fast can you generate blocks. To measure this one can use a lower difficulty than the network difficulty.