The pre-installed app selection is spotty but it does cover the basics. The calendar app can sync with multiple online accounts from Google, Yahoo! and others (as long as they support the CalDAV protocol). The Month view splits the screen between days of the month and an agenda for the selected day. Calendar accounts are color-coded.
Unlike the phonebook, the calendar app is capable of sending information back to Google's servers so it's not a one-directional sync (and it's automatic to boot).
The Notes app keeps things organized into separate notebooks. You can attach multiple images to each note. Hitting the Share button creates an email and copies over the text, unfortunately attached images do not go through.
The clock app has analog and digital views and lets you set up multiple alarms. Each alarm can have its own ringtone, snooze and repeat. The app also features a timer and a stopwatch.
Firefox OS has co-opted Nokia's HERE Maps for its default mapping solution. There are both map and satellite views available and you can also enable public transport and live traffic views (where available).
HERE Maps can plan routes for cars and pedestrians, public transport routes are also supported in some countries. Keep in mind this is just route planning, there's no voice-guided navigation.
You can save maps for offline use. Before you hit the Download button, HERE Maps will show a preview of the maximum zoom level. This feature doesn't download the full map details, but even so the download can run into tens of megabytes per city.
You can have only one offline map saved at a time and you need an active data connection to plan routes even inside the saved area.
One app that will certainly be useful going forward is Software update. It automatically checks for updates (you can do it manually, too) and handles download and installation. The update history keeps track of installed updates.
Firefox OS has a Power Save Mode, which can turn on automatically at a preset battery charge threshold (5%, 15% or 25%). This mode disables data, Bluetooth and geolocation.
A rich app store is one of the most important features of every smartphone OS. The Marketplace is where you get Firefox OS apps and the good news is you don't need an account like with other app stores.
The default view shows featured apps and a list of popular and new. You can also browse the store by category.
The app selection is slim at the moment, but some high-profile apps are already available. We've covered Twitter and Line already, but we also found Box (the cloud file sync utility), Airbnb, Soundcloud, games like Candy Crush and Cut the rope.
The app store also offers an Office document viewer (which supports Office 2007 files), a file manager and voice-guided navigation.
Before installing apps there's no list of permissions, but you will be asked about individual permissions as they are required by the app. A nice feature lacking in Android and iOS is that you don't have to grant permanent permissions.
You can review app permissions from the settings menu where you can change the previous settings. You can set them to Grant, Deny or Ask. Overall, Firefox OS provides great granularity when it comes to permissions, but we still think it would be more user-friendly to see the permissions required by the particular app before installing it.
Another privacy-minded feature is Do Not Track. This feature tells apps (and any advertising platforms they might use) that you do not wish to be tracked. Keep in mind that this feature doesn't guarantee your choice will be respected.