BUGS!

That's why.

Bugs fixed, try again.

Also! PEOPS may still sound better to some folks. It does completely random and non-sensical stuff while mixing sound that, by some law of Quantum Uncertanty, could possibly make some things sound better to some people. That's not something I can replicate, since I don't care to add the "omg random schrodingers cat in my plugin" factor to my code.

Also: for continued discussion of SPU-X, please replay in the the new SPU2-X topic instead. Thanks.

I was wondering why this plugin was in the pcsx2 playground version and now it's absent from 0.9.6. What happened?

The playground branch is now a spinoff called spu2-x. This thread and the name spu2ghz now refer only to the official version.

Thanks for the answer, keep up the good work!