Samsung has sent out invitations confirming that its long-awaited third-generation phablet, the Galaxy Note III, will be making its official debut on September 4, on the eve of the IFA trade show in Berlin, Germany.

And it will be an event that will be watched as keenly by competing device makers as it will by productivity-focused consumers.

Although Samsung is often accused of being a fast follower rather than a true consumer electronics innovator, it can claim to have invented, or at least popularized the phablet -- mobile devices with a screen greater than five inches that combine elements of both smartphones and tablets.

When it launched the Galaxy Note, complete with 5.3-inch display and stylus back in 2011, also at the IFA in Berlin, it was treated as little more than a curiosity.

However, it went on to sell millions, spawn an equally successful sequel -- the Note II -- and to influence countless copycat products.

Two years on, LG, Sony, ZTE, Huawei and ASUS have all jumped on board the phablet bandwagon and there are persistent rumors that even Apple is considering much larger displays for future iPhone generations.

So, what do we know about the Galaxy Note III? First off, it is expected to feature a 5.7-inch AMOLED HD display, a serious processor with 3GB of RAM in support and as big a battery as possible. It will also feature much, if not all of the new Samsung-centric features recently unveiled on the Galaxy SIV, such as eye-tracking and smart page-scrolling.

However, unlike in previous years, Samsung might have to fight for attention. HTC will also be unveiling what is widely expected to be a phablet version of its rather elegant One handset and, unlike Samsung, it will have Robert Downey Jr to help out.

The company has already started teasing consumers and the press alike with Vine and Instagram videos which hit the web on Monday (along with "leaked" images) that hint that something "big" is coming and that feature an elegant man -- thought to be Downey Jr -- carrying a briefcase, alighting from a helicopter.

Should you care?

Phablets are not for everyone. Their sheer size means that many consumers will find them next to impossible to use with a single hand, but by combining features from both phones and tablets in a single device, they can offer the best of both worlds, particularly for those that want a bigger on-screen keyboard and the space to use two apps side by side.

Choosing a phablet

The device's biggest asset is its screen, so the higher the resolution, the better. For this reason, if a device is offered with an OLED screen, take it -- the colors and contrasts will be greater still, making it just as good for watching movies and gaming as for working.

A big screen needs a big battery. Because phablets are bigger than phones, they have more space inside for a battery. Its performance will be measured in mAh so go for the highest number you can find.

Stylus or no stylus? The truth is that any touchscreen device will work with a third-party stylus but some devices, like the Samsung Galaxy Note II are optimized for S-Pen stylus input which means that as well as being able to draw very accurate lines or highlight an individual letter in a page of test, they also offer other special features.

How deep are your pockets? This is meant in the literal sense. How is it going to be transported -- in a jacket, slipped into jeans or in a bag? The device will need to match your wardrobe. Likewise, is it comfortable and light enough to hold with a single hand and are there applications and features that optimize the screen for single hand input?