It's really a sneak peek, so using it as your everyday browser is definitely not recommended. Use it as a taster of how the browser will work with your web site and applications. Gecko will be completely open source, with the source code being freely available at mozilla.org. A cool feature is that Gecko can be used on multiple platforms, including Windows, Macintosh and Linux. It's amazing that, with the application's small file size, all the functionality of the standard browser will be intact.
Gecko is also amazingly quick.
The small size will make it great for products besides the PC, such as fax machines and television set-top boxes. Gecko works with all leading Internet standards. For this developer preview, Netscape has presented Gecko's engine in two ways. The Viewer is a thin shell of native code wrapped around the layout engine. You'll find regular web content, just use it to check out your web site and the layout engine's standards support.