The BlackBerry Z10 has gone on sale in the US on AT&T, before being available from T-Mobile on 27 March and Verizon from 28 March.

The launch is seen by many as one of the last rolls of the dice for the company after a global launch that started well, but soon calmed with retailers in the UK quick to drop prices to ensure sales continued.

Dogged by false rumours about the how secure the phone is and whether it is or is not being approved by governments around the globe for being secure, BlackBerry (formerly RIM) is hoping to put all that behind it and concentrate on a successful US launch.

READ: BlackBerry Z10 review

The phone will cost $199 (£130) on a 2-year contract, or $449 if you only want to commit to a single year, but will have a challenge ahead against the might of the iPhone, and newer more powerful phones like the HTC One that launches at the end of the month, and Samsung Galaxy S4 that will come at the end of April. And that's before you start to consider the Windows Phone 8 devices like the Nokia Lumia range which Microsoft is starting to gain traction with in the US.  

BlackBerry is trying hard. It's announcing new apps, and the promise of even more apps to come in the coming weeks, often seen as a shortcoming of platforms rivalling iOS and Android.

There are now over 100,000 apps that work with the new operating system, including Amazon's Kindle app announced this week, while service like Skype have now been confirmed. Like WP8 though, many of the big hitters are still absent.

Thankfully for BlackBerry, recent reports have suggested that the lack of apps might not matter as the traditional BB customer doesn't see BlackBerry as an app platform, but in such an app-dominated world, it's unlikely to help sway the run of new customers BlackBerry needs to regain lost ground. In 2009 it had more than 50 per cent of the market; today it has just 5.9 per cent.

In the UK, the company has been reluctant to detail sales numbers - normally a worrying sign - but has said that while two-thirds of those buying the Z10 already owned a BB device, a promising one-third where previous iPhone and Android customers disenfranchised with what they previously had.

However, this launch isn't the real test for the company, it's just a teaser if you will, for the launch of the true BlackBerry, the Q10 next month.

READ: BlackBerry Q10 pictures and hands-on

The BlackBerry Qwerty keyboard device that is the device most likely to appeal to the more diehard BlackBerry customers (Eric Schmidt, Google CEO, included). If it fails to convince the shrinking BlackBerry customer install base to upgrade, then the company really is in trouble.