I suspect that the validity of my results may be questioned by any or all of the manufacturers of the chipsets and products tested, since the configuration of Azimuth's system that I used doesn't simulate multipath, which MIMO technology depends on to work some of its magic. Azimuth's Channel Emulator (ACE) does provide this capability, but for the sake of simplicity (and due to limited time) I decided to not use it for this round of testing.
As a result, I can't say that these results represent the ultimate "truth"...if there is such a thing in WLAN testing! What I can say, however, is that the tests put all products into an RF environment quieter and more repeatable than that used by any other published reviews. The Azimuth system produced repeatable results that allowed me to observe detailed product performance characteristics that other test methods could never hope to provide.
That said, what's the bottom line? Well, contrary to my previous tongue-in-cheek article, I have to join the chorus and advise against buying draft 11n products at this time. With high prices, immature drivers and firmware, no guarantee of upgrade to standard 11n when it's released and now - shown for the first time - evidence that some current products doesn't even perform better than 802.11g at lower signal levels, I can't think of an upside that justifies the expense and hassle.
In spite of vendor claims to the contrary, draft 11n has a long way to go until it gets to a maturity similar to what 802.11g had when draft 11g products started to ship. The industry and consumers would be better served if the manufacturers went back to their labs and standards meetings, hammered out the details and bugs and re-launched these products in dual-band form when they were really ready to ship.
And this "don't buy" includes Airgo Gen 3 products, too, since my testing didn't reveal any sign that Airgo has fixed their "bad neighbor" problem with legacy 11b and g products operating on Channel 6. More on that, and the results of interoperability and neighboring WLAN testing can be found in Part 2.