Laptops are great, but a hybrid form-factor is just better given it can suit different needs. You can use it as a tablet for watching movies, pair it up with the stylus to doodle and connect it to a keyboard for typing-intensive workflow.
On this front, both the iPad Pro and the Surface Pro 6 are identical, and you can multi-task with either.
While both the iPad Pro and the Surface 6 Pro are very capable devices, the final decision will come down to your needs.
If you need a device that can run full-strength desktop apps, you should opt for the Surface Pro 6. However, you have a simpler workload and need something for composing emails, editing photos/videos, and web browsing, get the iPad Pro.