BlackBerry had paused the rollout of the app after an unreleased version of the BBM for Android app leaked online prior to the app's official release on the Play Store, 'which resulted in volumes of data traffic orders of magnitude higher than normal for each active user and impacted the system in abnormal ways'.
Even the current rollout is based on a waitlist with access being granted first to users with a BlackBerry ID, and to people who registered their email address at BBM.com. Here's our initial take on the BBM for iOS app.
BBM is a free download from the iTunes App Store (and Google Play store) (download/waitlist links if possible) and anyone can sign up for the service through a BlackBerry ID which is required to log-in into the app. If you don't have a BlackBerry ID, you can create one by providing your email ID and choosing a password.
After signing-in, the BBM for iOS app assigns you a PIN in a manner similar to BlackBerry Messenger on BlackBerry links with the phone's unique PIN number. It's worth pointing out that if you sign-in to BBM on another device with the same BlackBerry ID, it will ask you if you'd like to switch the account to the new device. So, one ID can be used only on one device.
You can then add friends by sharing your PIN with them via SMS, email and social networks in addition to QR codes. It's worth pointing out that they'll first need to add you in order for you to send them messages via BBM. Even if two iPhones have the BBM app installed the PIN would first appear in Messages and requires other the user to manually enter it. BlackBerry mentions that this 2-way opt-in is in fact a security feature giving you control over who adds you.
The BBM for iOS app looks like it's been just ported from a BlackBerry 10 device in terms of the user interface, complete with swiping to the right gesture, to reveal a slide out menu for Chats, Contacts, Groups, Updates and Invites.
It's worth pointing out that only text, emoticons, voice notes and pictures can be shared in chats, at this point in time. We tried sending documents including PDF files from a BlackBerry phone but the transfer failed.
Unlike other chat apps such as WhatsApp, Line and WeChat, BBM doesn't support video file transfers and sharing contacts. It also doesn't offer push to chat, however BlackBerry mentions that BBM Voice (voice chat) will also be introduced to BBM for iOS and Android, in the future, in addition to BBM Channels (broadcast groups) and BBM Video (video chat).
On its native BlackBerry OS platform, BBM offers voice calling through BBM Voice and video chat through BBM Video (only on BlackBerry 10). If you're part of the Beta zone, you also get access to Channels. It allows sharing files other than just pictures, location, contacts and appointments.
It would be interesting to see how BBM evolves and competes with other messaging apps, as the playing field is now much wider. Overall, it's an efficient port, with a few transfer limitations that will hopefully be ironed out after the rollout is complete.