Jolla, a company made up of former Nokia developers, is out to create the best open source mobile operating system with its Sailfish OS, based loosely on MeGo. Until now the Jolla phone itself was \u20ac400 - a pricey way to access the OS.Now Jolla will be releasing a version that works on Android as a launcher later in the year. Since Sailfish supports Android apps this will be an attractive prospect for many. We used it for only half an hour and can't wait to get it installed.READ:\u00a0Jolla, the first Sailfish OS smartphone, gets official specs announcedWith Microsoft also trying to jump on Android for its personal promotion, competition is fierce. Does Sailfish OS stand a chance?Swiping is smarterThe goal of Sailfish OS is to make navigating the handset simple and universal across apps, without buttons. Much like LG's Knock, the screen can be double tapped to unlock the handset. Then swiping is all you need, a swipe up from the bezel will display notifications, wherever you are in the OS.A swipe left or right goes back to the homescreen, which is a layout of the currently open apps. A swipe down from the bezel shuts the current app, while a swipe down from the top half of the screen slides you along a top menu to take actions relating to the page. That's basic navigation, which we found didn't even require thought after a few minutes of use.Personalise inside and outJust as third-party developers can change Sailfish OS, third-party hardware makers can do the same. Cases with built-in NFC chips can be clipped on the phone to activate a download of a new theme automatically. So if you've got a case with your favourite band on it that will also set them as your background, load a track as your ringtone and download the official app. This is totally open and has huge potential for case manufacturers.Another example here was a small E Ink screen windowed on the rear of the handset. In this case it was showing the time, but as YotaPhone has shown us this could be great for storing an image or ticket when the phone's battery has died.Smart gesture recognitionOne great example of a third-party case was from iProtoxi which created a gesture recognition back cover. It even included a snazzy light for the Jolla logo, but this does more than just adapt looks. The logo can illuminate in various colours to notify of an incoming call while the phone is face down. Then a user can execute gestures to take action: hold a hand over the back to mute the call, swipe across to answer it.The idea is that new hardware can be added to Jolla without having to get a new device. We asked if this would work with Android devices but it was pretty clear they're not sure if that's possible at this early stage.First impressionsIf there's any proof that open source mobile operating systems work it's Android. Both Microsoft and Sailfish OS want to get involved, and with Sailfish bringing open source software as well as hardware the possibilities are huge.Using the UI was easy and, dare we say it, fun. But the most crucial thing here is that everything is open so developers can help it change and grow in the direction users want it to go.We can't wait to download the Sailfish OS skin on to our Android device in the coming months.