BlackBerry Messenger has been topped in the Google Play store, have you installed and using it? or you still in the dilemma whether to install the App or not. I'l tell you the four reasons why to install BlackBerry App in Your Smartphone.

1. Touch with your BlackBerry buddies
Presuming you have a friend using a BlackBerry, the chances are he or she is addicted to BBM and pretty much refuses to use other IM services. BlackBerry fans are a special kind of people and you're better off not arguing with them about their devices. They love 'em almost as much as Apple fanatics love products designed in Cupertino.
2. Another channel for communication
Why not be available to other people? You never know what the future holds. I have pretty much every IM client running on my phone. While I don't use many of them, few friends did ask to connect with me on services I thought no one uses. Luckily I had those apps installed on my phone. And I don't consider myself any kind of a super-networker; quite the contrary.
3. The software is actually good and secured
Even though you'll likely stick with IM apps you've been using before, I do suggest you to try out BBM. From what I've seen, the software is well polished and is a pleasant to use.
4. If you think BlackBerry's going to die, you'll end up owning a piece of history
Folks who think the Canadian company is on the brink of existence will be able to say they own a piece of history on their phone. It's not exactly a piece of Berlin wall, but it could turn into a “valid relic” as well.