iPad Pro is great. The thinner glass means that it has a better feel than Wacom Cintiq, at least for me. There is less offset between the pen tip and the brush stroke because of that thinner glass. Brushes do much better at thin to thick and stroke variation than they do in desktop Photoshop, in all three of the apps listed below, IMHO.
Procreate is great and affordable and the upcoming 5.0 (don't think it's out yet) looks really great. Nice brushes, easy to figure out.
Adobe just released Fresco, a painting app. The UI is super simple. Arguably, too simple with not enough brush controls. But quite easy to learn since you can't actually dig too deep. You can sign up to unlock all features. It'll be $10/month but they give you the first 6 months free and presumably you can cancel before it starts charging you. Probably not worth a subscription fee, imho, but worth doing a trial of even if only to just check out their wet on wet brushes (live brushes). A major benefit, though, is that you can import any of your Photoshop brushes and they work great, though the overall controls of those brushes inside of Fresco is very limited.
Clip Studio/Paint is great. The brushes are not as "real" feeling but they have great controls and this is the app that loads of comics artists have changed over to. This is a full featured app and is deeper and more robust for overall art production not just paint.
So, there are a few options to try out and all of them are pretty great. Check them all out and see what you personally like.
Oh, and it seems a full featured Photoshop should be released sometime soon. If the brush engine is good, that might be a great option, though it will undoubtedly have a subscription model as well.
