The update to OS 10.2.1 for all the BlackBerry 10 devices have actually made things really easy. You can now easily install Android apk files and there has been noticeable improvement in the smoothness across OS. Yes, there have been cases of bad battery life and occasional unresponsiveness, but by and large, things have really improved.
To check out the battery in terms of numerical percentages so far, you had to use a third party application for your device, but things are a lot more easier right now. though the solution does not give you the battery percentage like say it works in an iPhone where the percentage is displayed always, it still works.
To check the battery percentage of your device, all you need to do is to swipe up from the bottom bezel of your device like you would when checking out the peek feature of your device. The icon on top of your device which displays the battery in a bar graph will automatically change to percentage of remaining battery. The feature is simple, easy and since peek is something you do plenty of times during a day to check your missed notifications, it comes in handy too.