It took me a long time to get used to Photoshop. (After PSP and GIMP)
Now I love Photoshop and I can hardly do anything in Paint shop pro. I did a couple of PSD advanced photo editing courses which turned me on to photoshop.
People must have been wondering why I did the course because I didn't own a camera at the time. Then I was introduced to the incredible photoshop plug ins. Most of them are only compatible with psd and there are lots ! Everything for psd, smoke, lightning, scatterlight and there are heaps of tutorials on the web to show you how you use them.
I can't render big scenes in poser. I always see something that isn't right and have to stop the render. I remember the days when you got up in the morning to see if the render came out alright from the night before. I'm not a gambler any more. In psd I'm in control. However, I've heard that Poser7 can handle big scenes now.