Par3n1 I have heard that the Koetsu does not sound that great on the Michell table and that the sound gets really laid back and somewhat soporific. I use a Benz-Micro M2 which sounds really great, although I don't think it was a significant step up from the far less expensive Benz-Micro silver I was using earlier. I know that both Ortofon and Dynavector cartridges go really well with the Gyro Se.
As for the QC power supply, I made the plunge recently and feel it is a worthwhile investment. However, I also upgraded the clamp and applied the denso damp, which is half the cost of the QC, and feel that it is a better investment that the QC. I would definitely go that route before changing the power supply.