Updated: read our full review of the T-Mobile G1.

The world's first Android-powered handset has finally hit the market under the guise of the T-Mobile G1 with Google, and it certainly doesn't disappoint in its 'Google-y-ness'.

First impressions are of a fairly functional business phone, with trackball and a slide-out QWERTY keypad a nice BlackBerry-esque touch.

It should be remembered that HTC is a firm with a fast growing reputation in the smartphone market; the Touch series is already proving popular and the coup of picking up the first Android phone is a real feather in the Taiwanese manufacturer's cap.

The interface

Lest we forget, the reason we're here is to look at the OS, not the handset itself. The touchscreen and key interaction might be limited by the handset, but what about the actual Android OS, the one everyone has been bleating on about for so long?

Well, it's nicely laid out for starters. The icons that you like most can be placed wherever you want on the home screen, and you can wipe that left or right to access more applications you've decided need home screen loving.

The pull out menu and the fact you can 'pull down' open applications is very nice too... it works well and feel very intuitive.

The access to Google's applications, such as Mail or Maps, is very easy, and you can tell they've been formatted for this OS, as the simplicity of use, such as having your mail laid out in a long list, is easy to see and feel.

We're impressed... and you can tell there's going to be a lot of new and innovative things that come out of this open source project from the Open Handset Alliance.

The G1

The slide out keyboard has a nice feel to it; the keys aren't too far apart and the whole thing sits nicely in the hand in both landscape and portrait mode, though operating the trackball with one hand and using the touchscreen was a little bit tricky.

However, extending the screen to reveal the QWERTY keyboard had a slight Side-kick feel... we'd rather have a bit more slider-phone slickness to it if we're honest.

It's tricky to chat

Messaging, be it MMS, SMS or e-mail, is only available via the QWERTY, and the little kickblock at the bottom of the handset, where the call / terminate, menu, home and back buttons are housed, get right in the way when you're typing.

However, let's look at the negative points right now: no accelerometer, no 3.5mm headphone jack, the handset is a bit bulky (though it does have a keyboard) and there's not even a hint of multi-touch.

Though we were a bit dubious about the lack of accelerometer, as it had been talked about in great length in previous rumours and prototype handsets.

"I haven't heard of it [the accelerometer]. It's not in the kit when the phone comes out of the box," said a spokesperson for T-Mobile.

However, we found a 'Compass' application that seemed to work in the same way an in-built accelerometer might work... so whether the hardware is there and developers haven't got hold of it yet in this first generation... we're very confused.

Perhaps you'll be able to download applications to make it work in the future or something.

The phone also doesn't come with video playback out the box either... you have to download an application to be able to do so.

While these are real negative points for the handset, it does show the power of Android. If there's a problem, give it to the development community. They'll sort it!