The Sony Ericsson Z550i is a competent and well designed mid-range mobile phone with a number of excellent features. It combines sleek and stylish looks with a 1.3 megapixel camera, FM radio, Bluetooth connectivity and a music player.

The Z550i has a flip design and features a unique vertical external display. The display is quite slim and has a deep blue backlight, so it stands out and gives the unit a touch of class. Although the screen is not colour, it still does an adequate job of displaying information, showing time, battery life, reception and the current profile selected. As usual, it also displays caller ID information as well as indicating when you receive a message.

The Z550i feels solid and well built, although it is almost impossible to flip open with only one hand. This issue aside however, we quite liked the phone's design. It looks reasonably sleek, thanks to a business-like brushed steel finish combined with metallic black edges, and is comfortable to hold into your hand. This style is continued on the inside as well. Flipped open, the Z550i reveals a soft blue backlit keypad and glossy black screen bezel. The keypad is fairly flat, but for the most part it is pretty comfortable, so you shouldn't have too many problems punching out long messages.

Sony Ericsson has kept the controls simple, with a five-way navigational pad, two selection keys and back and clear buttons. There are also volume control keys on the right hand side of the unit, which can be used for both adjusting in-call volume and media playback.

The display is fairly noteworthy for a handset in this price range. The Z550i utilizes a TFT (176 x 220) screen that is capable of 262 thousand colours. Overall its performance was above average, with a bright, vibrant picture displayed throughout our testing. It is therefore ideal for using as the camera viewfinder, or for viewing pictures and video clips. Furthermore, the Z550i display also has surprisingly good horizontal and vertical viewing angles and performs quite well in sunlight.

The Z550i has a solid list of features, headed by a 1.3 megapixel camera. This is fairly standard for a model with these specifications; fine for photos to use as wallpaper and in MMS messages, but not good enough for any sort of real photography. The lack of a dedicated camera button is a downside, although a quick press of the up button on the five-way navigational pad fires up the camera application.

What did impress us however was the list of camera shooting modes, which include panorama, frames, burst shooting, night shots, negative and black and white effects as well as a 10 second self-timer. The burst mode was our favourite; four photos are taken in quick succession with one press of the shutter button, which is great for capturing fast moving scenarios such as sports, although the lack of a flash and excessive image noise make this feature somewhat less useful.

Other features of the Z550i include an FM radio with RDS (Radio Data System), support for standard push email (POP3 and IMAP), SMS and MMS messaging (with T9 predictive text input), Bluetooth connectivity and full HTML browsing. The Z550i also includes a fairly standard media player for music and video and this supports both MP3 and AAC files. With just 25MB of on-board memory, Sony Ericsson has also included a M2 (Memory Stick 2) slot for extra storage, although there is surprisingly no M2 card in the sales package.

We were impressed with the clarity of calls on the whole. The hands-free speakerphone is loud and clear but the volume of the Z550i earpiece could have been slightly higher. In noisy environments such as walking on a busy street, the phone was a little difficult to hear.

According to Sony Ericsson the Z550i is rated at up to 5.5 of hours talk time and up to 320 hours of standby time. We found these figures very close to the mark, having to charge the unit once every two to three days, which is about average.