Samsung is the master of the slider phone. It has produced model after model of sleek, jet black handsets that hide away the keypad when not in use, without losing you sight of the main LCD screen.
The Z720 might seem like it is a simple update of previous Ultra models, and the D900 in particular. But although the family heritage is obvious, there is something rather different about this phone. They've been tinkering around under the bonnet to produce what is probably about the hottest handset you can currently lay your hands on.
You can see from the outside it looks cool and unpretentious, and at just 14mm thick is one of the slimmest sliders around. But built into the 80g shell there is not just a 3G engine but one that has been tuned to provide the mobile broadband ride of your life.
Yes, this is, despite its size, one of the new breed of HSDPA (High Speed Downlink Packet Access) handsets - able to use the latest 3G network data rate enhancements to offer download speeds at up to four times that of a 'normal' 3G phone, and 28 times the speed of a good old-fashioned GPRS model.
It is not just the size and shape of the Z720 that appeals. Samsung has turned its back on the sensitive touch-activated semi-hidden buttons of the E900, and has gone back to using a more traditional set of control buttons, with softkeys and angular joypad providing the main interfaces.
A generously sized 2.1- inch quarter VGA screen is provided which is more than adequate for most 3G services - and just about big enough for enjoying mobile TV and web browsing services
The main camera lens is hidden from sight, and is only revealed when the keypad slides open. This helps to protect the optics from scratches and greasy smears - an important point if you are going to get the most out the 3-megapixel picture power that this handset offers.
The camera's default mode presents a curiously cropped version of what will be recorded (so as to use up the whole expanse of TFT), but this can be altered to give a more useful view of what you will actually be taking.
However, as this is a 3G phone, there is also a secondary lens connected to a simple VGA camera, which is there to use when video conferencing. The video call screen is well laid out, with a series of icons along the bottom that allow you easy access to alter the layout of the two video pictures, as well as other options; a very nicely designed piece of software.
This particular handset has been produced and set up for use on Vodafone's network (hence the V tag in the name), and the customisation means that network features that might be buried are readily to view. There is a menu option that takes you straight to the mobile TV browser pages, for instance. However, we believe that the phone will also be available in SIM-free form before long from specialist retailers and possibly other operators.
The onboard user memory is an adequate 20MB, but the MicroSD card slot is positioned within easy reach along the side of the phone, so that you can provide gigabytes of extra storage for video clips, music tracks and more. The headset uses a proprietary minipin socket to connect, making the use of other wired headphone difficult; however, this can be forgiven as there is provision for the use of stereo cable-free Bluetooth headsets.
The digital music player puts on a good performance through the supplied headset, with a lyrical bass response and reasonably-squeak-free rendition of the higher notes. It is more than good enough to get you absorbed in your favourite tracks. There is no equaliser to adjust tones but there is a "3D" option, to provide a pseudo surround soundstage.
The built-in camera is a cut above those found on most current mobiles. It is not just the 3-megapixel sensor that is worth crowing about - which on paper should be capable of producing A3 prints on a home printer without seeing the dots. It is also because this handset is capable of delivering much of the full potential of this resolution.
It has an excellent autofocus system that locks in on its target with minimum fuss and delay, allowing you to get right up close to your subject. A close-up shot taken from just a few millimetres away revealed the full detail and fine lines of an old bank note that we used to access detail and focusing accuracy.
The accurate lens adjustment is partnered by one of the best exposure and colour balancing systems that we have seen on a mobile. All in all, a first class set of pictures. You can almost forgive the lack of a built-in flash.
We were also impressed with the HSDPA service that the phone provides, particularly as you don't pay any extra to enjoy the increase in speed. As you access features in Vodafone's Live portal you only see it being employed for downloads via the usual 3G logo switching to a "3G " icon , although the boost in speed is always apparent.
Of course, there are billing checks and the usual server delays, but the extra speed is instantly noticeable and very welcome - particularly when downloading longer video clips, or when browsing freely through graphics-rich web pages.
A worrying aspect of HSDPA, according to a flier provided with the handset, is that when you are in this high-speed mode you may not be able to make or receive calls.
Ultimately, the HSDPA service could also provide higher quality mobile TV services - although at present these are optimised for the streaming capabilities of less-able 3G phones. Talking of TV, we are please to report that you can enlarge and rotate the moving image to fill the whole LCD picture area.
The one weakness of this phone is that it is not a smartphone, so you can't freely upload new sophisticated applications, or customise in the way that you can with some rival devices. Given the size, this is not an awful shortcoming, and the phone does its best to offer a full business package.
There is the full web browser, for starters, so you are not limited to Vodafone's content suggestions. And then there is the excellent Picsel document viewer, which is fast becoming part of the standard Samsung specification.
This allows you to read Word documents and PDF files as well as displaying JPEGs and HTML pages that have come attached to emails, or which have been uploaded to the phone. To provide light relief there is a reasonable selection of onboard games, plus a healthy helping of demos that you can try out before handing over your money for the full versions.
This is undoubtedly one of the best 3G handsets around. It keeps you up to date with the latest technology and services thanks to HSDPA, and does so without you having to compromise on size and design. In fact, this handset is so thin and light that you probably wouldn't even guess it had any high-speed capabilities. Highly recommended.