I used Gertrudis Pro with some success, but the interface was too small and difficult. When GMX PhotoPainter came out, it was a big improvement. But I was not thinking clearly at the time and didn't get it. Years later now, I went to buy it and noticed GMX PhotoPainter II is out. I really don't understand some of the interface design decisions on this new version. In some ways it's more difficult to use. But I badly needed its abilities, and bought it.
One thing to know. At first I could not register it with the key I bought. But the programmer told me to right click when launching and run as Administrator. I'm running Windows 7, btw. Anyway, that seemed to fix it. I was very relieved to hear back from him, because the forum there is dead and some people were not getting answers.
Also, for those of you who has lost your copy of the previous GMX, it's still there for download.
If any of you are using GMX II Windows, let me know what you think. From what I've read this Windows version unifies it with the Mac version.