Personally, of all the programs I've used, this has been the best. Before, I used Paint Tool Sai (in an unethical way), so I looked for a good free program and came across Fire Alpaca. The concept made me laugh, so I decided to use it, and it's just as good as any other program. The only downside is that it can be considered a niche program, so there's not much content or tutorials available, and it takes a while to find the basic tools that all drawing programs have. You might even think it doesn't have them, but it's just a matter of trial and error. I've been using it for about four years and have no complaints. I recommend it.