I am happy with the Companion One. The main reason I opted for it is the built in wireless access point and the optical out. My two primary uses are in the office with headphones (I have the AKG K550) and in one of my vehicles with an extensive audio system including an Alpine PRA-H400 Digital Time/Frequency Processor with optical input. I wanted the ap to use with airplay so I didn't have to plug/unplug my phone every time I left my desk and the portability (battery) of the unit makes it more convenient in the car where I was using an airport express which would have to reboot every time I made a quick stop at a gas station or something.
The negative is the range of the ap, at best it is six feet and sometimes even has trouble at a couple of feet, not a reel problem for my use as I set my phone right by it. I also don't like that it doesn't remember what mode you had it in so it always boots up for a cable connection, meaning an extra press and hold for a few seconds of a second button after every power up.
As others have mentioned it is a nice looking unit with solid build quality. The AKG-K550's have a high sensitivity so I always use the unit with the gain setting on low, I may get close to max volume for that range at times bet never felt the need to set to high gain. Haven't had a problem with battery life yet, a lot of times it is on for 6 - 8 hours though maybe only playing 4 or so.