I'm guessing that Evernote is the best of the rest (?) for those in a cross platform environment?
Evernote is certainly the most widely used and it works great in a cross platform environment. Some others have mentioned Notability but I don't have any personal experience with it. Evernote has always worked well for me so I've never been inclined to switch. I tried OneNote because it comes with my Office365 subscription but didn't like it.
Now throw in the pencil, is Evernote still the best option (handwritten notes)?