The high-capacity six-cell, 5,600mAh/63Wh battery that came with our review sample powered the X220T through no less than six hours and 41mins of MobileMark's Productivity test, with wireless turned off and screen brightness at 40 percent. This is an excellent result considering there are no compromises regarding CPU performance here, and with careful use this convertible tablet laptop should last you through the working day.
If you do need more time away from a socket, Lenovo's optional battery slice adds a second 5,800mAh/65Wh battery, almost doubling the above figure to a whopping 13 hours! Mind you, this does increase the X220T's weight from 1.89kg (or 1.76kg with the standard six-cell battery, the nine-cell is a £102 option) to 2.6kg and increases thickness from 31.3mm to 40mm. However, for many the trade-off will be worth it. The slice is very easy to attach, and plugging the charger into it will charge both it and the laptop's own battery.
When it comes to value, high-end ThinkPads have never been particularly affordable but arguably have been worth every penny. Unfortunately, the very reasonable $1,200 (£740) US starting price will see an almost direct translation to £1,147 excluding VAT (around £1,377 for the average consumer) on this side of the Atlantic - and that's configured with 2GB of RAM, a 250GB hard drive and the six-cell battery.
However, this is not actually as poor value as it might at first appear. As already mentioned, there's not much competition in the convertible laptop tablet market. The X220T's closest rival is probably HP's EliteBook 2740p, which starts at £1,107 ex. VAT. But then you're stuck with an older generation processor, smaller, slower hard drive, no digital video output, shorter battery life and, most importantly, the HP won't come close to the quality of the ThinkPad's IPS display no matter how good its TN-based screen is.
Is Lenovo's ThinkPad X220T the perfect tablet laptop? Not really, but it's as close as it gets. Sure, it's not cheap, its industrial aesthetic won't appeal to everyone, it lacks USB 3.0 and eSATA, and we would have liked a few more vertical pixels on the screen. However, with the excellent quality of its class-leading IPS display, amazing battery life, superb build quality and ergonomics, high-end specifications and ThinkPad reputation, this is the best convertible tablet laptop currently on the market.