I am using CLIP Studio Paint Pro!
You can learn more about it here (use google translate), you can buy it HERE by purchasing gold points via CLIP. I bought it with my credit card for roughly $65. If you want a translated version, download version 1.0.3 here (you must be logged in and have already purchased the software before, scroll to the bottom, the link is there) then go to this thread and follow the directions & download in the first post. Translated software! :)
CLIP is constantly updating and creating new AMAZING changes and adding new features so make sure you follow this thread to keep up with new english translations. Don’t update your software until the new translation is out, otherwise you’ll be stuck in Japanese mode until the new translation comes out.
Please don’t ask for a torrent or a free download of this program. All the people in the forums (& the japanese company) have been working so hard to get this program awesome for well over a year. At only $65 it’s really a steal and we should support it! :)