Given that the performance improvement in second generation 11a are real and significant, why aren't Atheros and its customers doing more to get the word out? In reality, I think Atheros has been making some attempts, most notably via a recent series of whitepapers including one named 802.11 Wireless LAN Performance.
Figure 7: Comparison of 1st and 2nd generation 802.11a
(click on the image for a full-sized view)
From Atheros whitepaper 802.11 Wireless LAN Performance
Used by permission.
Figure 7, which is taken from that whitepaper, shows a comparison of throughput vs. range for a first (Intel PRO/Wireless 5000 AP and PC Card) and second (NETGEAR WAB102 AP and WAB501 CardBus card) generation 11a AP and card pair. Although I can't directly compare the results from my tests made in a residential environment with Atheros' which were conducted in a typical open-office environment, I will say that the 2nd generation products should provide a much improved user experience for both residential and Enterprise users.
Strangely enough, I think that 802.11a may come into its own once tri-mode, dual-band (a/b/g) products - or at least those with Atheros 11a radios - start to be deployed. Despite its improved speed, 802.11g won't be the solution for everyone, due to its susceptibility to interference from 2.4GHz cordless phones, microwave ovens, and other neighboring 802.11b equipment. Since all tri-mode APs and routers with Atheros radios will use the second generation 11a chipset, many users' first experience with 2nd generation 11a performance may come via their interest in 802.11g. Talk about riding in on a Trojan Horse!