Vendors are trying to figure out what works when it comes to screen sizes, according to Geoff Blaber, analyst at CCS Insight.

One of the big product trends at IFAwas screen sizes between 4.5 inches and 5.5 inches, which include the LTE version of Samsung Electronics' Galaxy S II, HTC's Windows Phone-based Titan, Samsung's Galaxy Note and the Tablet P from Sony, which has two 5-inch screens.

So far, consumers have shunned products with screens around this size, such as the Dell Streak. But vendors including Samsung and HTC are hoping larger screen sizes will help them differentiate their products in a very competitive market.

"Today's smartphones are pretty difficult to distinguish when it comes to the customer actually looking at them in stores. Increasing the screen is a clear example of manufacturers trying to differentiate rather than following the established product classes," said Blaber.

Even though it is not alone, Samsung is to a large extent the company pushing this size category. At the Galaxy Note product launch, the company said it wants to create a new product category between current smartphones and tablets, according to DJ Lee, head of global sales and marketing at Samsung Mobile.