I used Paint Shop Pro (now Photo Paint) for many years, and felt pretty good about it for a long time. In my experience, the last few revisions of the program have added little value as far as features for a serious photographer, and the software's robustness has suffered.
About a year ago I decided move to the big-boy photoshop. I made this decision after getting frustrated with the poor performance and reliability of the Corel program. I downloaded demo versions of Elements and Photoshop and was, quite honestly, floored by Photoshop's performance and user interface. It took me a good while to get used to the different UI, but there are SO many improvements in the features, the workflow, the incredible robustness of the softare. Dealing with huge images, many layers, and still far outperforming how Corel would run on a much simpler project.
While Corel "has" many of the features and capabilities of Photoshop, they are so much better, faster, more fluid, more reliable ... in Photoshop.
In short (too late for that), while you can accomplish many of the same things in Photo Paint, getting there is not as fast, making changes is not as easy, the UI isn't as helpful, and you better save often, because the program will crash far more often.