As Doug mentioned, I am a big fan of the iPad pro with the Apple pencil.
Do you want to sketchnote live webinars for yourself or show others (via screen-sharing) what you sketch, while you sketch, Tam?
I very much like these apps for iPad pro: Work Visual, Sketch Club, Concepts, Explain Everything. But there are much more options. You can even connect the iPad with a regular computer and use it as a touch screen for computer software, somehow like a tablet (but better). The app to accomplish this is called Astropad.
The choices are huge and depend a lot on what you are used to (experience and comfort zone), what you want to do with it (while and after sketching), time and willingness to learn a new tool, and any existing workflow.
I like Work Visual because it is designed to be used in a professional setting, yet constrains the way to sketch to a very productive workflow. It offers layers, presets, different colors and sketching tools, two live output modes, video output (with the help of a software tool), and a clean and logical UI. It does not work with vectorized graphic nor does it offer infinite canvas.