I've had mine for over a year. Couldn't be happier with it. I prefer a warmer sound, and that's what it does to my CD player (the Musical Fidelity XRay).
One important tweak: buy the XPSUv3 - outboard power supply - to go with it. It kicks everything up a notch. Like everything else, you want to try at home before you buy.

How does it work if put between the preamp and power amp with phono, tape and CD input?

Never tried it there. I've only CD and phono sources, and I'm happy with the analog the way it is.

I have a sense that the results you hear in various configurations are too system-specific to be taken as general rules. I've tried it between pre- and power amp in my brother's solid-state system but really, Cheapskate nailed this one. It's best between a CD player and pre-amp (I have it between a Sony NC555ES used only for SACD playback and a BAT VK-3i and it's terrific) but the outboard power supply is a must. This of course doubles the price but since one power supply can feed three MF components it's a good buy if you're thinking of adding the X-CANv3 headphone amp or another MF piece in the future.

Roy E.