Designers have approached the concept of a business phone from two different directions. Some start with a PDA design and add phone functionality (presumably so there will be less of a compromise on usability and functionality). Others start with a mobile phone and add PDA functions -- while trying to maintain mobile phone convenience.
Four PDA phones were offered for review: the O2 Xda IIi, the i-mate PDA2k EVDO, PalmOne's Treo 650, and the Motorola A1000. The O2 and i-mate are full blown Windows-based Pocket PC's, the Treo is a Palm OS PDA, and the Motorola runs a fairly sparse Symbian OS.
The O2 and i-mate are the size and shape of traditional PDA's while the Motorola is a good deal smaller but still resembles a PDA. The Treo looks like a fusion between phone and PDA. Of the mobile phones with added PDA function, we tested the Nokia 9300, Blackberry 7100v, Sony Ericcson P910i, Siemens SK65, and the NEC N410i.
These models have evolved beyond typical mobile phones and now feature much of the functionality of a PDA. The Nokia is particularly interesting as it looks like a relatively large and clunky mobile phone with a typical phone keyboard and small display, but it opens like a clamshell to reveal a larger portrait display and QWERTY keypad.
The Sony is a large and chunky mobile phone that has quite a large display and a standard phone number pad that flips down to reveal a full QWERTY keyboard on the reverse side and the complete display -- similar in size to a full PDA.
This results in a "+" shaped phone featuring a full keyboard with the QWERT half on the left side of the phone and the YUIOP on the right side. Those with long fingernails may break quite a few opening the phone -- the lock is quite stiff and gives way suddenly.
The NEC N410i is a clamshell phone with a tiny display on the front face and a larger display inside, it retains a regular phone keyboard -- no QWERTY. In fact, this is the only phone that still looks like a phone.
Pocketability
There is no such word as pocketability (but there should be). Most men would prefer not to carry a bag, so a phone that fits in your pocket is important.
The weight and bulk of all of these phones renders them poor contenders for trouser-pocket transportation. You (and the rest of the people in the room) will certainly know they are in your pocket.
Although it is not quite available yet, you must also check out the next HP iPAQ 6500 - it is the size of a Blackberry 7230, but so much more capable; quad-band phone with EDGE, 1.3Mpix camera & LED flash, Bluetooth (no WiFi), GPS!!!!, and the usual PPC2003SE stuff (hopefully upgradeable to WindowsMobile5.0 in Oct or so).
http://www.brighthand.com/article/iPAQ_hw6500_Coming_in_September?site=SmartPhone
http://davesipaq.com/news/ipaq_hw6500_comparison.html
And here is a link to some recent forum comment about the size (smaller than a normal iPAQ), battery life (better than a normal iPAQ, not as good as a Blackberry!) and built in keyboard (very similar to Blackberry).
http://davesipaq.com/forum/showthread.php?p=35358#post35358
It is already released in Germany & UK (in theory at least!) and I'm hoping to see it in Australia in Aug or Sept..