A larger screen means a bigger chassis, and the 4211 takes advantage of this to offer a bigger keyboard than even the AA1 and to locate the touchpad buttons in the right place - below the pad, not either side of it. For us, that makes using the 4211 without a mouse a goer, something we wouldn't care to do with the AA1 or the original Eee.
That said, while our review unit came equipped with a Synaptics touchpad, many shipping units use Sentelic pads. It's claimed that most of the demo models on show used the superior Synaptics pad.

Standard SCC port array
This may be an issue if you want to install Linux - Sentelic pads aren't as common as Synaptics ones, so the driver support may not be as solid. On Windows, the new pad is said to be very sensitive, with movements often mis-read as a click. Tap-to-click can't be disabled. Some forum posters complain about the lack of a speed-scroll option too, but that's less of an issue, we feel, lack of features being less important than having features that work.
We asked DSG about this, and the company would only say that "there are no planned changes to the current model in the forseeable future". Alas, that doesn't tell us anything useful, so this is a true caveat emptor situation.
Our advice: ask to have the box opened and try before you buy. We're not saying there's a problem with the Sentelic pad, only that we haven't tried it and a fair few folk don't appear to like it. It may be fine for you, however.
The 4211's keyboard has a little flex, but it's reasonably solid and, because of it's size, good to type quickly on. It's way better than the smaller Eee keyboards in both size and feel, though there's not really that much to choose between it and the AA1's similarly Eee-beating keyboard.
COMMENTS
Re. warranty
No intention about it. Perhaps I wasn't clear enough, UK law provides a much higher level of protection than a warranty so, whilst you might have good reason to be concerned about PC World's service, at least you can reject goods which a warranty will not allow you to do.
In most case a buyer is advised to take a warranty issue up with the seller because of this.
Re. warranty
I think you are intentionally missing the point there. The quality of service is entirely different. Even if it doesn't change your legal protection you are getting a different product entirely. Who is to say that PC World even match the terms of the manufacturers warranty, there is often a difference between what a manufacturer has to offer under law and what they offer in reality.
With manufacturer support, at least for the Aspire One you can deal direct with Acer who actually know what they are doing, the device is collected, repaired and returned to your door pretty quickly. PC World support - well I shouldn't need to tell anyone here just how bad that can be. It's got to be even worse for those with linux versions who have to deal with the "Tech Guys".
Re. warranty
Under UK law your contract is with the vendor anyway. i.e PC World, whether or not it has a manufacturer's warranty. Your rights are unaffected and you are still afforded the same level of protection.
Warranty - Why PC World can offer it cheaper!
As someone who bought an Aspire One from PC World discovered, they have bought the warranty/support from the manufacturer. If it goes wrong then you are not covered by a manufacturer warranty and instead have to use PC World's "TechGuys" service.
So if it goes wrong you are basically screwed. With that crucial detail in mind, paying £20 extra to purchase elsewhere is a bargin!
This point needs to be covered in the review and potentially in a separate article as a warning to buyers. Those who bought Acer Aspire One's from PC World were at no point told that warranty obligations were not with Acer (who have been highly praised by users with fauly Ones) but with PC World who have a horrendous track record on support.
Looks like PCWB are for real
It looks like PCWB are for real - they hve shipped it. Should hopefully arrive tommorrow morning.
