What are some alternatives?
When comparing Tusk and Google Keep, you can also consider the following products
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
Sidenotes - Annotate the web.
OneNote - Get the OneNote app for free on your tablet, phone, and computer, so you can capture your ideas and to-do lists in one place wherever you are. Or try OneNote with Office for free.
Whimsical Sticky Notes - Visual project management using sticky notes
Simplenote - The simplest way to keep notes. Light, clean, and free. Simplenote is now available for iOS, Android, Mac, and the web.
Standard Notes - A safe place for your notes, thoughts, and life's work