I've downloaded Keep before, but decided it wasn't worth, well, keeping. With its new update which brought reminders, it has met my exacting standards (ha) and I'm going to keep Keep. It's pretty, it's useful, and I'm all for giving my information to Google.
Clear and simple structured notes app, which is Googles representation in this area! You can also choose date and time or a specify location for alarm!
P.S.: Also optimized for tablets and Android Wear!