I am taking part in the Caturday Art this week with four versions of the same photo. Two are with Lunapic, and two with Dreamscope.
I have been trying Dreamscope lately but have found the end results are much smaller than they were previously. Probably because they want me to buy the paid for version, but I can't see the point in paying $9.99 a month for something I won't use very often.
I prefer Lunapic because you can adjust how much filter you use and add as many as you want...and it's free!
You can see more art with Athena, the Cat Goddess.