Like the TX300, the T300 has a dark grey all-aluminium chassis with a light grey keyboard panel. It's a good-looking design, but the material collects a few too many smudges. In closed position, the chassis and keyboard make for a 22.5 mm-thick device, making it easy to carry around, but not quite as much as the Acer Aspire S7-392 or 13" MacBook Air.
There's some play in the hinge that connects the keyboard and tablet/display, so you have to handle the T300 with more care than most. Also, the display is a little too heavy compared to the keyboard, so the keyboard tends to move when you tap the touchscreen.
The chiclet keys feel comfortable to the touch, but they aren't backlit. The touchpad is nice and spacious (105 x 61 mm), facilitating the Windows 8 touch gestures.
With the exception of the SD card reader located below the display, all of the ports are found on the left side of the screen. By that we mean one micro-HDMI, one headphone/microphone combo jack and one USB 3.0 port (required to charge the keyboard). A few extra ports would have been more than welcome—Asus could at least have included a USB hub in the box. The wireless connectivity consists of Bluetooth and Wi-Fi 802.11 a/b/g/n, which offers a stable signal of 50 dBm from 5 to 10 metres away and -60 dBm from 20 metres away.
The Transformer Book T300 stays as cool as can be. The hottest temperature we picked up while running it full throttle was 33.9°C, so it's a great device to have sitting on your lap. The fan stays practically inaudible with a maximum of 35 dB(A) in otherwise silent settings.
The display consists of an IPS panel—probably some derivative of PLS—with Full HD resolution (1920 x 1080 pixels). We measured the contrast at 818:1, which is decent for a laptop, but its low brightness (maximum 262 cd/m²) doesn't help counter the glossy surface's glare when you're outdoors.
Grey colour temperature
The colours are astonishingly faithful as laptops and tablets go, with a Delta E of 2.6 (the human eye can't perceive differences below dE 3). In other words, colours onscreen look natural, the way they should look, which is a rare feat for this type of device. Equally close to perfection are the colour temperature (6,617 K) and gamma (2.2). All in all, I'd say this is a great display for exacting users who want a picture-perfect screen.
The sound quality is fairly typical for a laptop/tablet hybrid. The built-in speakers are far from breaking any records; they have relatively low volume and almost no bass (although that's no surprise once you see the two tiny orifices on the side that make up the speaker outputs). The mids are well-reproduced, though, making for acceptable intelligibility.
The model we were sent to review features an Intel Core i3-4010U processor, 4 GB of RAM, an Intel HD Graphics 4400 chipset and a 128 GB SSD. The observations above refer to all versions of the Asus Transformer Book T300, whereas the comments below apply only to the model we tested (see Models, Specs & Options at the bottom of this page). Available models and configurations may also vary depending on the country/region in which you live.
The Transformer Book T300 boasts one of Intel's new Haswell processors, the Core i3-4010U. It's a 1.7 GHz dual-core chip that handled most of the tasks we sent its way with speed and efficiency. It can take care of more demanding activities like photo and video editing as well, but in those cases patience can be a virtue.
As you can see, the Core i3-4010U performs just a tad (6%) less well than the previous generation of the i3, which was clocked at 1.8 GHz, but it outperforms the latest Pentium by a long shot (60% faster). Naturally, the Core i5-4200U comes in first in this selection. The T300's SSD allows for ultra-quick startup and shutdown times.
The HD Graphics 4400 chipset is no stranger to us. It's even slower in this configuration than in the Core i5-equipped hybrids we've tested. But the biggest reason for this isn't the processor, it's the RAM, which the graphics rely upon directly.
Concretely, you can't expect amazing gaming out of the T300, and certainly not in the screen's native resolution. Tablet-grade games from the Windows Store and older, less demanding titles like FIFA 13 will do just fine, but very few recent PC games will run adequately in Full HD with the settings on high.
MOBILITY / BATTERY LIFE
We were expecting a horror story after seeing that there's no extra battery in the keyboard this time, but the T300 gets astonishingly good usage compared to the TX300. It lasted for 6 hours of video playback (in airplane mode with the screen brightness at 100 cd/m² and headphones plugged in), whereas the TX300 lasted 4½ hours, despite the fact that it has an extra battery. This makes the T300 a good travel buddy.