You won’t regret the investment in an iPad Pro! I bought one a few weeks ago, and it really is very, very good. Drawing with the Apple Pencil on the iPad Pro made me fall in love with the device instantly. I did have a severe case of sticker-shock though, as the price was a little out of my comfort zone. That said, combined with Astropad, it is a very capable alternative to a Wacom Cintiq tablet (if you connect with a cable, over wifi the latency is annoying). And if you know the prices of those tablets, the iPad Pro is a steal! Yes, that’s my cognitive dissonance talking as well. 😉
My favorite app for real-time, on-stage drawing is Work Visual. Mostly because of the presentation option where you can zoom in on your iPad without the audience becoming dizzy (they just see the whole canvas).
For high quality drawings though, I prefer Procreate. So if I’m drawing solo, I use that.
When I need to create vector graphics, I start drawing in Adobe Illustrator Draw on the iPad Pro, then bring that to Adobe Illustrator on the desktop though Creative Cloud. Works like a charm! Comes in handy when I want to create VideoScribes as well (I then layer a transparent drawing-path on top of the image and export it to SVG).
Very recently, I’ve added Concepts to my favorite iPad Pro apps. It’s very similar to Adobe Illustrator Draw, and adds some nice touches with regard to interaction design that could make it my go-to app for vector based illustration on the iPad.