Having used various bone conduction headsets for years mostly from Motorola, I can say that they give fantastic crystal clear audio, tho without the range you need for a good music experience (do-able but not great)
It is definitely usable in a normal-medium ambient noise environment, with the added benefit of still letting you hear what is happening around you, that's a massive win. In the town I used to live in a road construction guy was backed over by a steamroller when listening to his ipod.
As to comfort, they are far far better than having buds in your ears (I hate buds) and the pressure required is insignificant, it's less than wearing a hat or glasses.
They are the perfect solution for this device in every way, the glasses are not meant for playing media, which is the only area bone conduction doesn't completely win.