The basic model of the Asus ultrabook family is the Zenbook UX21. Typical of the Asus Zenbook product line, this ultrabook has the thinnest design of any we have seen. It is lightweight but doesn't feel like it is going to break when you are holding it on your lap. However, compared to the best ultrabooks, the UX21 comes with a smaller processor, and less memory and less storage space, which is even more significant when you consider that most ultrabooks hard drives are pretty small to begin with.

Specifically, this Asus ultrabook has an Intel Core i3-2367 processor, a basic setup of 2GB of memory and a choice between 64GB or 128GB of hard drive space. The processor is still very powerful; it allows the computer to reboot from sleep mode within two to three seconds. With the available memory, you should have no trouble completing your daily tasks and routines. On the other hand, if you plan to play StarCraft II or do other graphics-heavy activities, you should probably seek an upgrade.

Screen resolution weighs in at 1366 x 768 (16:9), and the device has an 11.6-inch LED screen. Like other models in this Asus' series of ultrathin notebooks, the speakers are hidden, but they have great surround sound capabilities.

In terms of design, the Zenbook UX21 is a good Windows-based alternative to the MacBook Air. It has a wedge-shaped design that gets thinner from back to front, moving from 0.66 inches to 0.27 inches. The aluminum casing allows it to stay cool, and the aluminum resists scratches, which is bonus if you plan to take your ultrathin laptop everywhere you go. The keyboard's keys are spaced apart just right and almost bounce, making it easy to type. However, the keyboard isn't backlit.

The touchpad can be a little over-sensitive at times. Even hovering over the touchpad can cause the mouse cursor to flicker, so if you are using one finger to scroll and another finger gets close to the touchpad, the cursor moves. We found this glitch to be a little irritating.

The UX21 is pretty basic, and its features are right on par with other standard ultrabooks. It has two USB ports and a Micro HDMI output. It also includes a USB adaptor, which you'll need to use if you ever want to go wired instead of wireless since there is no Ethernet port. This device is also missing a memory card reader.

With Asus products, you get an overall enjoyable experience with customer support. Their products have a one-year warranty, and they offer live chat support. There is an email address listed, but be aware that you may have to wait a day or two for a response to your email. You'll also find forums that cover everything from parts to warranties.