I run a P25/RB600 and an looking to uprage from that at the moement. If you like what the Rega does I am not all that convinced that you would want a Linn deck, Try and hear the Avid Diva II, NA Spacedeck, and the Gyro. Either taking the OL arm with you, or selling the 3 and buying a technoarm as well.All good decks, but all different to each other. A P7 should also finds it's way onto the dem list as well.
Another possibility is to stick a OL DC motor on the P3, along witha Groovetracer subplatter. The problem with that is that the s/hand value when you do change is at best unpredicatable.