Hey
I've used Sketchbook Pro, Photoshop and Manga Studio in the past, but since I got the iPad Pro and Pencil (I saw that @will-terry is still struggling to get a hold of the pencil - I was super lucky, but man - I would NOT be happy if I were Will), I've just been using Procreate for everything. It can handle fast sketching and full on paintings on large canvasses. Here's a quick Ronnie Wood caricature sketch I did today using Procreate and I'll probably start painting it tomorrow.
Apparently Affinity Designer is being ported to iPad Pro at the moment. I've never used the desktop version though.
Ace