I can't think of many versions of Painter that I have not liked. Maybe one, several versions back ... However, the current versions 9x and by the looks of it, 10x are really the icing on the cake.
I haven't had to upgrade my computer for several years. I'm just content with my current set up (works for me). However, if I were to purchase a new Intel Mac, and monster monitor, I would consider buying Painter 10x manditory.

For now, Painter 9x is working fine. And after using 10x for a bit, and seeing that there are not a huge number of differences. I'm happy sticking with 9x until I do upgrade to a faster, larger computer.

I've always used Painter, since v1.0, and will continue to support the best painting program in existance. Painter rocks ... no matter what version you use, always has!