ZDNet put together a nice review of a range of products that are based on the draft 802.11n spec with disappointing results: Data rates for the draft N products (even those at close range) were disappointing. Atheros- and Broadcom-based products delivered between 60 and 80Mbps, while the Marvell-based Netgear RangeMax Next almost reached 100Mbps. These data points are much lower than the manufacturers' claimed rates of around 300Mbps. As you may have guessed with a draft spec, interoperability is best among draft N products that use the same chipset.

To read more about the draft N review:
- see this article from ZDNet