The swedish usability consulting firm inUse did a usability review of four mobile phones including Apple’s iPhone, the HTC TyTN, Sony Ericsson W910i, and Nokia N95. Users performed common tasks such as making a call by dialing a number manually and then by calling a person from the address book, change volume during a call add a new contact to the address book, create a new calendar event and more.

The result should be useful for those who are trying to convince their IT department:

Stunning. The iPhone has introduced a new interaction paradigm to the world, in an uncompromising way that proves that “less is more” when it comes to true user experience.

Some other interesting quotes from the report include:

Most of the subjects did not mention the HTC at all when speaking of which device they would prefer. […] Only one of the users was able to carry out all tasks [on the HTC] without the assistance of the test leader and all five users had severe difficulties with at least three of the tasks.

What is it then that makes the iPhone different? Most importantly, it has removed one level of abstraction by allowing the user to act on objects using the finger directly on the phone’s surface. The difference between this and having to press keys on a keyboard and watch the screen to see what happens is striking.

The full report is available in PDF from the inUseful blog.