Each device maker is also claiming substantial standby time and battery life for their ultrathin laptops. Acer says the Aspire can last for up to 6 hours of regular use, and Apple says the Air will last for up to 7 hours when doing wireless Web browsing. Acer is also claiming an astounding 50 days of standby time, which is 20 days more than the Apple's 30-day claim for the Air. But it's important to remember that manufacturer claims often differ from third-party battery life tests. So it's best not to count on Acer's claims until the S3 has been thoroughly tested by PCWorld.

For a detailed look at the latest Air's battery life results, check out .

If you're looking for something sleek to slip into your backpack, both the Air and the Aspire S3 are solid choices. The Air is slightly lighter at 2.96 pounds versus the Aspire S3's 2.98 pounds. As for height, both devices measure 0.68 of an inch at their thickest points. But the Air can slim down to just 0.11 inches, while the thinnest point on the new Aspire S3 is just over half an inch.

Now that are finally being launched, some of the concerns about the new laptop category may finally be answered. There have been rumors about Ultrabooks failing to meet Intel's promised , manufacturer's , and rumors about as-yet announced Ultrabooks from device makers such as . This week, we'll start to get a better picture.