BlackBerry maker Research In Motion whose new Playbook tablet has been widely criticised by reviewers is struggling to deliver in what has become a hostile Smartphone and tablet market.Last night shares in the company plunged 11 percent due to a big slump in sales of their Blackberry smartphone. RIM executives said that they expect shipments of BlackBerry smartphones for the quarter, ending in May, to be at the lower end of the range of 13.5 million to 14.5 million forecast in March. It also said it expected a shift in the mix of devices to lower-price models.

It’s the latest in a string of setbacks for RIM as its struggles to compete with arch rival Apple and the likes of HTC and Motorola.

RIM said the lower shipments and mix shift will result in revenue slightly below the $5.2 billion to $5.6 billion estimated forecast in late March. RIM said it expects to achieve full-year earnings per share of about $7.50, anticipating “strong revenue growth” in the third and fourth quarters of the fiscal year.

Motorola Mobility, which competes against RIM in the smartphone market by selling phones built on the Google Android platform said that its revenue from mobile devices jumped 30 percent to $2.1 billion. The company said it shipped 4.1 million smartphones – up from 2.3 million a year earlier -as well as 250,000 of its new Xoom tablets, which debuted on February 24.
Motorola Mobility’s loss narrowed to $81 million in the first quarter from $212 million a year earlier.