I don't know the U-Turn, but in good shape (referring mainly to the condition of its springs) your PL-600 is an excellent turntable and worthy of a much better phono stage than the Schiit Mani. In other words I see no need to give up on the Rogue Ares.
However, as mulveling notes and for the same reason, I would certainly get the Ares Magnum rather than the vanilla edition. Or, if your Audio-Technica is also an MM, you can always add a good step-up later on if you decide to try an MC cartridge.
However, as mulveling notes and for the same reason, I would certainly get the Ares Magnum rather than the vanilla edition. Or, if your Audio-Technica is also an MM, you can always add a good step-up later on if you decide to try an MC cartridge.