Hi Suzie,
I discovered it today, too and love it. I'm surprised nobody else joins in to praise it here, I always thought it is the tool that everybody had been waiting for for ages

.
I haven't had time to play around a lot either, but noticed that when you double-click on a specific brush another window opens up showing the brush in its original size which is really helpful to see details.
At first the program didn't run and I contacted the programmer. He answered within 30 minutes and now it works marvellously.
Two thumbs up for Luigi.....