Hey there. I know I’m commenting on a pretty old topic so this might not even be helpful to you, but I would absolutely recommend Procreate if you never got it.
It has all the basic functions (paint brush, smudge brush, eraser brush, ability to change brush opacity and size, layer functionality) of all decent drawing apps, but really, I think it’s also the most usable and worthwhile of any I’ve seen out there. Partly because the creators had a pretty good app already and they make good updates, partly because of how they allow user interaction and creativity.
For the former aspect, you have a pretty big variety of brushes (I did a cursory count of all the ones that come with the app purchase and the number comes out to about 130 brushes), which is already nice. What makes it genius to me is that they also let you use any brushes you have when you’re smudging or erasing. So basically, if you’re willing to experiment and try different things, you can really do just about any texture style you want in your digital art.
For the latter aspect, they have a forum where you can post various things and talk to each other as you wish. What I like about it is that you can download brushes that others have made. Sometimes they’re free to use, other times you will have to purchase to be able to download them. Either way, it’s a good example of positive user-developer interaction.
It also has a few other special things about it! You can easily make time lapses to share your process or do like a live broadcast of your work. You can do different blurs on layers, change the color balance, or distort the layer itself. You can make color palettes to use. And the app allows you to save your images in different formats like pdf, jpg, png, etc. which is useful if you’re wanting to make Episode overlays from your own art.
The only drawback I’ve encountered is that it will max out your layers at a certain number depending on how big you make your canvas dimensions. (For example: 4000 x 4000 px allows you a max of 29 layers) Understandable though, since one app can probably only handle so much at once. Another slight downside is that some of its features can be difficult to understand; however, there are also plenty of Youtube videos by various artists who happily share their techniques or give instructions on how to do something. 
Overall, I’ve had only really, really positive experiences with Procreate. When it’s been bad or frustrating, it’s because I’ve become upset by how my artwork is developing or by a lack of personal progress - not really anything stemming from the app itself.