I had to go look up on their website about demos... they have an awesome one https://www.artrage.com/demos/ I guess you can't save, export, or record scripts [I suppose you could screen capture if you wanted to keep a record or play with it as a layer in another program; just maybe don't share such around publicly unless you buy the full license version ] but everything else is fully functional and there is no time limit.

I tried Corel Painter back when the wet oils and real watercolors were new... and I think I was still using my old laptop. They froze and crashed the program because they were so heavy/powerful but, wow, they were gorgeous.
I think ArtRage is acceptably comparable [or as kacey said it above] for quality results, and surpasses it for processing lightness and ease of use/learning curve, and definitely on cost.