It's getting there. Most of the current high-end devices, including the iPhone 5, iPad and Galaxy S III support 5GHz. I would expect within a year it will be pretty much universal on new devices, even though it isn't now. Plus when you consider the number of the aforementioned "big three" devices that are in service, there are already quite a few users who would benefit from 802.11a already. If you are getting interference issues, another benefit with the 5GHz spectrum is that you won't experience as much interference from everyday things such as microwaves.