If the TZ18 looks familiar, that’s because it’s the spitting image of the TZ17, which graced these pages just two months ago. We can’t complain, as this version is as desirable as the original, but Sony has made a major change under the covers. Gone is the 100GB hard disk of the TZ17, replaced by a 32GB Samsung solid-state disk (SSD) – one of the very first laptops to contain what some consider the death knell for mechanical hard disks.

We’re yet to be convinced by that, but SSD does have a number of advantages over mechanical disks, which, for all their tried-and-tested years, still rely on precision moving parts. As they’re prone to physical stress, extra layers such as head-parking software become necessary, and a single, heavy blow can render the whole disk extinct. Also, seek times are higher because of the need to get a physical head to a specific place on a disk. And, in a product where battery life is the name of the game, SSDs take up significantly less power than their spinning equivalents.

But the proof of the pudding is, as they say, in the benchmarks. The TZ18 produced superb results in our battery tests. The TZ17 set a high bar with a staggering light-use run of 7hrs 17mins. As this test makes minimal use of the hard disk, it seemed unwise to expect great things, but the TZ18 still managed to beat its predecessor by 37 minutes, bringing it to within touching distance of the holy grail of eight hours – the working day. That also beats Sony’s own seven-hour estimate. And our intensive-use test showed the clear power-saving advantages of the SSD: where the TZ17 ran to 3hrs 7mins, the TZ18 ran a whole hour more – an incredible 4hrs 19mins, flat out.

The SSD does come at a cost, though, and we don’t just mean the TZ18’s whopping price tag. SSDs are only just past the point of being prohibitively expensive, and price and capacity is still some way off the sweet spot. As it is, the TZ18 comes with 32GB of storage, which, once formatted, equates to merely 23GB of usable space (there’s also a hidden 7.45GB recovery partition). Into this rather cramped space, you need to get Windows, plus your documents and any applications you need. So although the TZ18 might be perfect for entertainment on long flights, you can forget about keeping films on there for very long, or even a decent-sized music collection. Luckily, the built-in DVD writer is on hand.

The processor is the same 1.2GHz Core 2 U7600, but we still saw an improvement in its application benchmark score from 0.57 to 0.59 for the TZ18. The RAM is unchanged at 1GB, though Vista sometimes runs smoother with 2GB.

The screen is also unchanged, being the same 1366 x 768 glossy panel of the TZ17. And we remain as unconvinced by it – for all its shiny attractiveness, the glossy finish is highly reflective, and fluorescent office lights are a particular problem. Images are at least punchy thanks to the apparent boost in contrast, but we do ultimately prefer a matte-finish.

And, of course, the TZ18 still looks incredible. When closed, it’s just 30mm thick, with the LCD being remarkably slender at 4mm. The flush keyboard is solid and surprisingly comfortable to type on, and neat touches abound. A fingerprint reader sits between the mouse buttons, and a range of chrome-effect media buttons sit along the front edge, with a pair of media card slots occupying the other side.

But the TZ18 has to keep company with another beautifully designed and made ultraportable – the Sony G11 (see A-List). The G11 offers a significant saving, and while the TZ18 may be better looking, the G11 is no ugly stepsister. When it comes to price, take note that the business-class G11 costs $3700, leaving the TZ18 looking distinctly private jet at $4300 (though DigitalYes is selling it for $300 less).

The TZ18 is undoubtedly an aspirational machine, and the SSD hard disk adds some tangible benefits in terms of battery life. But the storage capacity also borders on the impractical. The G11 might not be quite as jaw-droppingly attractive, but it offers better battery life and similar performance in a slightly lighter package, besides having far more hard disk space while offering a saving of some $300.