Here's how it breaks down for me:
- MacBook Pro Retina and iMac 5k for high fidelity visual work: Unity, video editing, Adobe apps, etc.
- iPad Pro as second screen for communication, web research, documentation
- iPad Pro for any sketching/pencil ideation work, note-taking in meetings where people aren't using laptops. - Because it fits easily on an airline tray table and because I upgraded to the 4g version, it's also my go to for travel working enroute.
- iPad Pro to start things, sketch things, type up initial notes, rough out new Keynote decks, etc; finish up and polish in the matching Mac apps. My top tip here for Keynote on iPad is that you can select multiple objects if you hold on the first one.
- Games are interesting because the difference in form factor, input devices, and gpu means some games are better on iPad Pro and some are better on Macs (or Xbox, PC, Switch, etc.)