Timely is one of the best looking apps available, including a tablet mode for those who have a spare device sitting on the bedside. The app was so well designed and received that Google actually bought the company. As a result, it's now completely free, yet is still jam-packed full of useful features.
We have standard alarm features, wake up challenges, and cloud sync so any settings are on all of your devices. Most of this is built into Android now though, too.
Set themes to make the app any color you'd like, turn your phone over for snooze, and try their widgets on a phone or tablet for even more useful features. You'll love this app.