You have to look closely to spot the differences between the original T-Mobile MDA Compact and this updated Compact II version as they share the same size and weight, screen dimensions and resolution and have the same controls.

The most obvious change is that the Compact ran on Windows Mobile 2003 and the Compact II uses Windows Mobile 5, but the updates don't bring much to a PDA as they work best on a pure smartphone such as the Orange SPV C550.

Before we continue, it's worth mentioning that the MDA Compact II is another device from HTC - a Taiwanese company that manufactures Windows Mobile handsets for most of the major mobile operators.

Internally, the Rom has increased from 64MB to 128MB while the processor has changed from a 416MHz Intel PXA272 to a Texas Instruments Omap 850 195MHz.

Despite the dramatic drop in clock speed, the two models seemed equally responsive.

Two versions are offered - graphite and a slightly less macho baby pink alternative.

The Compact II suffers from the same annoyances as the Compact, the major difficulty being that you have to use a virtual keypad to make phone calls.

At its heart this is a PDA, so basic phone functions such as sending a text are unnecessarily complex.

The Compact II is more effective when you send emails and browse the web, but you are obliged to hunt and peck at the keypad with the stylus as the touch sensitive screen is too small for you to use your fingers.

A year ago the original MDA Compact had a significant advantage over the competition as its screen was relatively large.

Although it still strikes a reasonable compromise between a mobile phone and a PDA, there are smaller alternatives with similar screen resolutions and regular keypads.

We were impressed with the original MDA Compact, but the only real enhancement to this updated version is Windows Mobile 5 - we had hoped for a more.

Without a devoted keyboard, many of the features of this new Microsoft operating system can be awkward to use.

If you're after a PDA-style phone, we'd recommend looking at other HTC models, such as the O2 XDA Mini, which includes a slide-out Qwerty keyboard.

This handset is also available on T-Mobile under the MDA Vario badge.