I use PSP v5 all the time for cleaning up images along with a supplement JASC program called Image Robot for batch processing. I've used PSP since v3 and am quite pleased with it. For information I process about 300 photos per week with PSP.
As someone said, it is second only to Adobe Photoshop.
My advice would be, if you're looking for something to start learning in-depth and plan on getting heavily involved with image editing and will be doing lots of touch-up work, output to print, artistic work, etc. you might be better off spending the time to learn the Adobe program. I personally think it is slightly more complex and harder for beginners, but it's the de-facto standard and there are *lots* of free helper apps, information, actions, and other goodies available on the web.
On the other hand, if you're just going to be an occasional to moderately heavy user then install PSP and enjoy. It's a great program, particularly for the price.