Ok... my 2 cents:
Although I am registered here for over 2 years, only now I am starting to trial Voxcommando.
Because my house took more time building than I initially expected, only last week I have connected and powered up my mic installation.
By the way... I was truly happy to find out that VC now supports Microsoft Speech Recognition Engine.
So... let me describe you my whole house mic system:
I have 2 Gentner AP800 mic mixers and a Gentner AP10 telephone gateway. I have 8 ceiling mics installed through the house from various manufacturers: Crown, Astatic, Beyer Dynamics and Audio Technics. All of these were bought from Ebay. An used AP800 should sell for $100 or less.
The Gentner AP800 is widely used in home automation scenarios. It supports 8 mics, features rs232 control, and has all the features one should need for every scenario. One of the cool features is that if you feed an audio source (TV, music, whatever) it can 'substract' that audio from the mics feed. For example: you can issue voice commands on a room playing loud music.
I have the mixers connected to my server running Eventghost. When VC detects a command, it tells EG, I query the mixer for the gated mic and know the location where the command was issued. I use it also has an intercom system.
This is, of course, theoretically because only now I will power up the mixers and start playing around. I'll have to set gains and volumes for the whole thing and try speech recognition accuracy.
Anyway... this just to say that the Gentner's AP800 are a very good option for whole house systems.
Regards,
Mike