Samsung's U600 slider hogged the number one spot in the mobile charts throughout late summer, so it was only natural that its successor, the G600, should leapfrog it to the top within days of hitting the shops.

The SGH-G600 hails from the same Ultra Edition II range as the U600, and carries a few modifications that may have the U600 buyers kicking themselves for not delaying their upgrade a month or two.

The most notable improvement is the 5-megapixel camera. Up from 3.2 on the U600, the G600's camera sits at the top of the phone, hidden away when the slider is shut but revealing its lens and LED flash when slid open. Pressing the camera hotkey on the side of the phone activates the camera application. This key then acts as your shutter key, but give it a half-press and it's also your auto-focus. A full press takes the photo, and there's none of the annoying delay we experienced when taking photos on the U600.

There's a wide range of settings on the camera app, from the usual white balance and macro settings to multi-shot mode, ISO setting (100 to 800) and the biggest selection of colour effects we've seen on a camera phone; they range from black and white and sepia to emboss, green and aqua. There's also an arty mosaic mode, although we're not sure what its purpose is. Once your photos are saved, Image editor lets you adjust brightness and contract, add effects and blur or warp images.

The camera takes good photos at all resolutions from 320x240 up to 2560x1920, and is great for everything from party snaps to arty landscapes. It also captures video at 640x480. Our only reservation is the usual gripe about the LED flash, which leaves its tell-tale blue glare on indoor pics. For a 5-megapixel camera, we're disappointed that it doesn't have a more powerful xenon flash instead.

The stylish grey-and-black G600 feels more solidly built than recent Samsung models, and thankfully the overly touch-sensitive selection keys of the U600 have been replaced by proper clicking buttons. The slider opens with a satisfyingly solid click too. This extra build quality has added to the thickness, but at just 15mm this it's hardly likely to trouble the stitching on your pocket.

The large keys on the keypad are very responsive and the interface attractive, right down to the dynamic home page which displays a photo of a national landmark (in the case of the UK, the Houses of Parliament, in France it's the Arc de Triomphe and so on) and clouds if your signal strength falls. Fans of personalised desktops can even build their own themes based on photos or supplied patterns using a simple theme creator.

The Samsung user interface still isn't the easiest to use though, and a few idiosyncrasies spoil the otherwise well-designed menu structure. Why, for instance, is Bluetooth hidden away under Applications, and why, when you have to enter a word manually while writing texts, does it default to all upper case? Customisation is also less than intuitive, with tone selection hidden away in the profiles section of the Settings menu.

A media player and easy-to-use FM radio complement powerful in-built speakers to complete the G600's multimedia armory, and the 40MB of internal memory can be boosted using the 1GB microSD card included in the box. One disappointing oversight is the lack of 3G coverage - the G600 is only equipped with GPRS and EDGE, although that should be fast enough for most mobile web users.

By entering this year's 5-megapixel bunfight without adding too much to the size of their offering, Samsung has created a solidly built phone that should give the Nokia N95 and Sony Ericsson K910i a run for their money.