PSP plugs I find are some that seem to work really well in a given situation, and then don't shine as well in others.
Case in point, I use the NobleC EQ on some vocals to try it out and fell in love with it. Tried it on a rythym guitar and had to tweak more that I thought I would, but finally found something I liked, but it didn't shine like I thought it would. However, when I turned the NobleC EQ off, that's when I realized what it really had done. It did much more to help that guitar sit in the mix than I originally thought.
I have the PSP Oldtimer Comp and it works pretty much the same for me. Sometimes it really just shines as soon as I stick it on something. Other times it takes some tweaking.
I am really happy with PSP products. I just got Waves Gold bundle. And I also got about three to four new PSP plugs. I am more excited about trying the PSP plugs than the Waves plugs. : )