Conclusion
In terms of performance, the Linksys shows its superiority against both the Gigabyte and Microsoft offerings. If you are purchasing on pure performance, I believe the Linksys is the way to go. However, this does not mean that the Gigabyte does not hold its own against the other routers. It has performance on par with the Microsoft router, but it has a few features going for it that puts it above the Microsoft. Firstly, it supports Atheros' accelerated G mode, as do a lot of other wireless products. This compatibility substantially increases the number of products you can purchase while maintaining performance. Also, the physical dimensions make it easier to mount, whether on the wall or on a desk (or even on the side of a case). With no major flaws in its design and functionality, I can give Gigabyte a recommended rating (I guess I'm a sucker for good-looking parts).
Rating: 8/10
Link: http://tw.giga-byte.com/Communication/Products/Products_Wireless_GN-B49G.htm