I have been using PSP since version 7 (currently I have PSP9 licensed). When the PSPX came out I installed the trial, extended it and now that the extended trial is over I'm probably not going to upgrade since it doesnt' seem to be worth the upgrade price.
They promised support for my digital camera raw files (CR2 from EOS350d) but so far they haven't been working. I decided to invest to RawShooter Premium which appears to do pretty much all of the basic operations (crop, resize, WB, exposure compensation, straighten, sharpen, RAW->JPEG translation) and is much faster than the PSP. For the operations that the RSP doesn't support, I'll be using PSP9.