a user interacts with Eva using microphones. the VoiceTracker mic would be nice if used in small rooms with low background noise. it lets you interact with Eva at anytime, but you have to pause any music or audio book before you can speak a command (this gets annoying). since my main usage scenarios are music and audio books, i switched to wireless mics because you can speak commands while the background noise is still playing. these have been working great, and i just have them in the same places where you would put a remote control. my main issue with these mics is they dont have any sort of security.
been playing with bluetooth hand/headsets. the ThinkGeek retro handset is a nice form factor. the main problem is you have to hold a button for 5 seconds to turn it on ... way too long. the handset scenario is pick it up, speak a command, hear the answer, and set the handset down. the 5 seconds waiting before you can speak a command is an eternity. on the other hand, the handset adds a private speaker, so if music were playing out the main speakers in a zone, you could still hear speech responses from eva over the handset speaker, without having to pause music playing over the main speakers. so the bluetooth handset needs a physical switch to turn it on/off; or a tap-and-talk button. to be really bad ass, the handset would need a dock that charged it, and it automatically switched on when removed from the dock.
also tried a traditional bluetooth headset. again, this takes 3 to 5 seconds to turn on or off. for a headset, this is less of an issue because you wear it. you turn the headset on, and then just use it from room to room. but to have music follow you, you still have to tell Eva which zone to transfer music to, because the headset would not be tied to any particular zone. also, you wouldn't hand an ear piece over to a friend to use (without ear condoms) ... a mic handset is less disgusting (cover the mic before you cough). plus i'm not commanding eva non-stop. the goal is to reduce the number of commands that have to be spoken, so just having a mic within arms reach is fine. finally, i think wearing a bluetooth headset makes you a douchebag.
another problem for both devices is range ... 33ft is for personal area networks, but doesnt cover a home. that might be solved by the AirCable bluetooth range extender. so neither of these bluetooth devices are going to make it into my own setup. but i am going to keep looking to see if there are some other bluetooth devices that are more user-friendly, because the private speaker is a compelling scenario.