i use my ipad pro for 100% of my illustration, there are so many excellent tools, and the pencil makes it very easy to draw. That being said, i do need to use 2 or 3 apps to acheive what i want a lot of the time, as there isnt 1 perfect solution yet.

As for the design side of things, i find Affinity design to be really good, but its no where near ready for print production ready work. most controls are too basic and while you can achieve a lot, i wouldnt use it for anything beyond a mockup, or i would get a design 75% of the way tehre and then need to switch to my mac to finish it off (which can be done in Designer on the desktop)

I see a lot of potential, but with todays update meaning i would need to buy a new ipad pro and a new pencil, and ditch all the accessories i already have for my ipad pro, its not making me want to keep investing in it.