I can't answer the exact question but, a friend went from a Rogue Perseus to the RP-5. It was a big improvement all around and the Perseus can perform well in the right situation.
The Perseus lacks a standby mode so, it took a few hours (like 5 or 6) of on time for the Perseus to sound its best. Is it correct that the RP-1 also, lacks a standby mode? If so, it also needs a long warm up to compare to an RP-5 if both are to be on equal footing, not to mention also having the same tubes in each for an apples to apples comparison (they ought to be equally warm for the comparison).
Speaking of footing, my friend also put a set of Herbie's Tenderfeet under the RP-5. That was a very significant improvement.
Side note: I am temporarily borrowing the Perseus while my Calypso is in for repair/upgrade. With a pair of RCA clear tops in the rear tube positions and pair of current production Mullards in the front, the Perseus sounds very good. The tubes make all the difference between just ok and really pleasing sound. My friend is running Mazda NOS tubes in the RP-5.