I would recommend against the Rega P3. The arm is so limiting in terms of its lack of easy adjustability (VTA and azimuth). I think the Technics suggestions are a better choice for numerous reasons.
Recommended cartridge for Rega 3
I have been slowly upgrading a 2-channel system as retirement gift to myself and I am looking into the Rega 3 turntable. Right now I am using a Pro-ject Debut III with an acrylic platter and Ortofon Blue. The rest of the system is a Rotel RA1572 Integrated Amp and Monitor Audio Gold 200 speakers. Just looking for suggestions. Thanks