CNET has reviewed a WLAN notebook card from Belkin, here's a snip from their full test report:

Belkin's new Wireless G Plus MIMO Notebook Card adapter proves that newer is not necessarily better. In our tests, it offered slower maximum and mixed-mode throughput than its older counterpart, the Belkin Pre-N PC Card; it also achieved less than half of the Pre-N PC Card's speed at long range. The G Plus MIMO line (including a companion router) is part of Belkin's push to span the divide between plain-vanilla 802.11g devices and the first generation of (expensive) MIMO devices, both in terms of performance and price. The Wireless G Plus MIMO Card's performance almost overshadows its other enticing elements, which include simple setup, a comprehensive configuration utility, WPA and VPN support, and an unlimited warranty..



Link: CNET