Glenn Fleishman has a long piece over at Wi-Fi Networking News that expands on some of the issues I covered in my post of a few weeks ago. It also provides some new insight into some of the issues regarding 11n and its operation in the 5 GHz band.
Glenn gives props to Apple for its decision to not allow use of "wide channels", i.e. channel bonding or 40 MHz mode, in the 2.4 GHz band. It should also be noted, however, that Intel has done the same thing in its new draft 11n chipset. Buffalo Technology didn't go quite as far with its new dual-band gear, choosing only to default to 20 MHz mode in the 2.4 GHz band. It's still possible for a user to manually switch the Buffalo gear to channel-bonding mode, however.