The X1's good looks and strong hardware are hampered by frequent performance lag, an unintuitive user experience and its jaw-dropping price tag.

We still remember when we first saw images of the X1 after its original announcement back in February. At the time Windows Mobile smartphones were shrugging off its bulky size and boring business looks, with phones from HTC beginning to look sleeker, but nothing at the time looked like the X1. The arc-slider and full QWERTY keypad were eye-catching, and the 3-inch touchscreen looked stunning.

Design
For once, the photoshopped images haven't lied. The X1 is every bit as stunning in the flesh (or in the brushed metal, as the case may be). The arc-slider slips fluidly on its rails with a satisfying snap when opened or closed. The four-row QWERTY keyboard is excellent, even if it seems a tad too small at first glance. Using the keyboard is easy, even at night, thanks to its bright backlighting and well spaced buttons. Unlike many keyboards on smartphones the X1 dedicates buttons to common punctuation, saving you from having to dip into symbol menus to find an "@" symbol for email addresses, etc.

The touchscreen has a WVGA resoltuion (800x480) which is 2.5 times higher than that of the iPhone 3G. This sounds like a good thing, and for watching videos it is; however, we've found this resolution fills the screen with sharp, but tiny characters. Some menus, like the alphabetical listing in the contacts menu, is entirely illegible because the letters become so small. Even with the fonts adjusted to the largest setting we've still struggled to read some elements of the screen.

Importantly, this means the X1 isn't a finger-friendly touchscreen. During our testing, we've relied on the stylus for input more than with any touchscreen we've seen for a long time. This is disappointing; using the stylus significantly slows down input and hampers the usability of a touchscreen phone.

Panels
Sony Ericsson is putting a lot of faith in its extensive Windows Mobile skin called the Xperia Panels. While companies like HTC also skin WiMo with a custom interface to increase ease of use, the Xperia Panels is a system offering numerous interface options. Out of the box, the X1 has seven panels pre-installed with more panels available from a Sony Ericsson web portal.

Our first impressions of the Panels weren't particularly favourable. The seven pre-installed Panels range from being too cluttered to use to being utterly useless. For example, one of the more attractive panels featuring three swimming goldfish barely shows notifications and offers no shortcuts to frequently used apps — hardly an interface you'll leave active for very long.

It wasn't until we downloaded a Facebook panel and another by Windows Mobile modders Spb that we saw how excellent this system could be. The Spb Panel acts exactly like the one the company designed for all Windows Mobile handsets, and the Facebook Panel is as good as any app on the iPhone — in fact, it looks more like an iPhone app than a WiMo app.

Features
Under the Panels the X1 is a pretty standard Windows Mobile. At its announcement during World Mobile Congress earlier this year, the X1 was set to be best-in-show, with features to blow everyone else out of the water. That was almost a year ago and now the X1's connectivity combination of HSDPA, Wi-Fi and AGPS isn't exciting, but is nonetheless essential to the productivity of customers looking to use the phone for business purposes.

For pleasure seekers, the X1 is a pretty mean multimedia machine. As mentioned above, videos look amazing on the the high-res display, and one of the pre-installed panels is the Sony Ericsson Walkman music player menu. Our only recommendation is that you upgrade the bundled headphones to a pair capable of producing a well-rounded sound — the 'phones in the box are too light on bass to be of much use.

The X1 also sports a 3.2-megapixel camera with auto-focus and an LED photolight. These specs aren't extraordinary for a smartphone these days, but its performance was much better than expected. The photos we took during testing showed good colour and focus, and even photos at night turned out well — the bright LED managing to illuminate subjects within about two metres of the lens.

Performance
Exploring the phone's performance, through accessing common apps and the menu structure, has provided us with a real mixed bag of results. The X1 runs a 520MHz Qualcomm processor with a massive 256MB RAM, and for the most part this is sufficient. Executing Java apps and opening menus is pretty pacey, and launching other programs, like Opera Mobile, requires only a few seconds of loading time.

Xperia Panels seems to require more resources, however. We noticed considerable lag between pressing the Panels' soft-key and having the interface active, and again after a Panel was selected. For this reason we tended to remain in the panel we found most useful, though this obviously defeats the purpose of having nine active panels to choose from.

Responsiveness, or the lack thereof, seems to be the crux of the first impressions for just about everyone we showed this phone to. While executing applications seem fine, there are too many times when the X1 stops responding to input — immediately after sending an SMS, for example.

Battery life cycles were, in our experience, low to average. Sony Ericsson estimates a whopping 10 hours talk-time for its 1500mAh battery. We saw only about a day and a half between charges, with moderate use of calls and messaging, and push email active throughout the cycles.

Overall
More often than not, we either love or hate the phones we see. The X1 is a rare example of a smartphone that has grown on us over the course of our review. The first few days tested our patience as we turned to the stylus too often, and indeed this element hasn't changed, but with the right Panel interface active, using the X1 is easy enough. In truth, we could do without the Xperia Panels. Of the 15 available at launch, we might use two, and the Panels system seems tremendously resource inefficient.

That in mind, the X1 is a well-featured phone that checks all the important smartphone boxes. We don't love the X1 — the frequent lag spikes are frustrating, and there are definitely cheaper and more intuitive smartphones available — but we think it's a gallant first attempt at a WiMo smartphone and a very attractive handset at that.