While there are only five preset buttons on the front, that's actually a little deceptive. You can "favorite" more than five stations (Asus claims up to 250), and you can pull them up using the "favorites" menu. This is a nice advantage over the Grace Wireless Internet Radio, which only has five presets (although you can get around that limitation by bookmarking favorites on the online Reciva service, which is accessible through the radio).
The radio has clock, alarm, and sleep functionality. When the unit is turned off, it brightly displays the time in large letters, which is great for glancing at it across the room. The alarm can be set to play back a standard beep, a preset melody, or tune into the last station you were listening to. Of course, there's no snooze button or other alarm niceties, so we doubt many will use it as their main alarm clock. The sleep functionality works as you'd expect, with the your time limit options limited to 15, 30, 60, 90, and 120 minutes--plenty, in our opinion.
While the Asus Air is pretty well-featured for a Wi-Fi radio, there are some missing features that buyers will want to take note of. Unlike the Grace Wireless Internet Radio, the Air can't pull music off a networked PC (although the Grace wasn't flawless with this functionality). We also really liked the Sony VGF-WA1's built-in lithium battery--allowing you to carry it around your house, wherever you have a Wi-Fi signal--and the Asus Air is limited to traditional power. Still, even with these drawbacks, the Air has a solid feature set that is by far its strong suit.
Sound quality might not be as important on a tabletop radio, but it's still a major concern. But before we start talking about sound quality, let's get some caveats out of the way. First, remember that Internet radio is compressed by nature (sometimes rather severely), so no matter how good the radio is, it's not exactly a "hi-fi" experience. Secondly, keep in mind that the Asus Air is a tabletop radio and sounds like one--don't expect the same sound you get out of a real component-based sound system. And lastly, like many tabletop radios, the Asus Air is limited to mono sound.
Even with those lowered expectations, the Air's sound is uninspiring. We had the Grace Wireless Internet Radio on hand, and we were able to put the Air and the Grace head-to-head. While audio comparisons can often be subtle, this one wasn't--the Grace sounded considerably fuller than the thin and tinny Air. Once we cranked the volume past the halfway point, we'd occasionally hear buzzing and rattling from the speaker. While we're guessing most listeners could put up with thin sound, the occasional buzzing really killed our listening experience. Sure, at times, the Air could actually sound OK, but once we switched over to the Grace the difference was instantly noticeable and preferable.
Wi-Fi connectivity wasn't as strong as we would have liked, either. We had the Air set up in the same environment as the Grace Wireless Internet Radio, and we found it to be a bit less reliable. There would be times when the signal strength meter said we had full strength signal, but it still said "connecting" and wouldn't play any music. We found the trick to be to force the Air to reconnect using the configuration menu, but that was annoying. Once it started playing though, it was mostly glitch free, although there were a few cases where the Air had to "rebuffer." You can adjust the amount of buffer the Air uses in the setup menu--we stuck with the standard 4-second buffer--but you can go up to 8 seconds if you consistently run into problems.
If you really don't care about sound quality or mostly listen to talk, you probably won't mind the Air's sonic shortcomings, but we think most people will be better off with the better-sounding (but less-featured) Grace Wireless Internet Radio or the portable Sony VGF-WA1. As much as we liked the Air's feature set, ultimately we just didn't enjoy listening to it as much as the better-sounding alternatives.