The calendar has iOS touch with a dynamic icon that shows the day of the month. There are three views - Daily, Weekly and Monthly. The Memos tab in the app is equivalent to Agenda view - it shows a list of all events, past and future.
The app can easily handle several online calendars as well as the local calendar and you can selectively hide calendars to keep things tidy. You can add multiple reminders for each event and search through all events.
The clock app supports multiple alarms, each with its own repeat time, ring tone, volume, snooze interval and note. The app also offers a world clock, a stop watch and a timer.
The calculator is a just a skinned version of the stock app - it has big, easily thumbable keys and you can swipe to the left to bring up the advanced functions (trigonometry, square root, brackets, etc.).
The NearMe Notes app comes pre-installed. The app lets you create complex notes with text, images and hand drawn notes. The gimmick here is that each note has a location associated with it and only notes that are "close by" will be displayed.
There's a weather app too, which shows the weather with various videos for the various weather conditions.
The Tools folder is preloaded with a few apps that you usually get from the market. There's a Flashlight app (that's virtually identical to the HTC app), a sound recorder and a 3D compass.
The Google Play Store features several scrollable tabs - categories, featured, top paid, top free, top grossing, top new paid, top new free and trending. You can also check out the Play Picks, Apps to Watch, Apps Highlights and Editor's Choice categories on the Home tab for more curated app lists. The Recommended for you list is based on what apps you've installed and what your Google+ friends have liked.
Apps usually have several screenshots (some even offer a demo video) so you can get an idea of what the app looks like before installing it.
You can also check out comments and ratings, as well as the number of downloads and so on, to help you decide if the app is worth it.
The Google Play Store is full of all sorts of apps, but in some countries it also offers music, movies and TV shows, books and magazines.
The Oppo R819 has a built-in GPS receiver, which managed to get a lock in under a minute. If all you need is a rough idea of where you are (within 150 meters) you can use the Cell-ID and Wi-Fi network lock, which is very fast as well.
Google recently revamped the UI, but the basics are the same. Maps offers voice-guided navigation in certain countries and falls back to a list of instructions elsewhere. You can also plan routes for bicycles and public transport. A nice addition in the latest version is that Maps shows you a couple of alternative routes like the desktop version of Google Maps.
For navigation, the map will cache the data it needs and will reroute you offline (so you don't need a data connection along the way). The Navigation app itself had its UI polished to match the rest of Maps.
You can also search for nearby POI and go into the always cool Street View.
Popular places around the world feature pictures and reviews by people. Street view isn't available everywhere, but it is growing in coverage and is the coolest thing we've seen on a Maps app to date (that includes Aerial view in iOS).
You can save maps for offline view, which caches them on your device's storage, but keep in mind that not all map info is saved (meaning not everything down to street level like businesses, POIs, etc.).