It's the same app. In North America, it's called Seeing Eye GPS; in Europe, it's called RNIB Navigator; and in Australia, it's called Guide Dogs NSW ACT. Sendero (or now Aira) uses blindness agencies in each region to help with marketing and brand awareness.

Yes it pulls data from FourSquare, but other sources too such as Open Street Maps and also allows you the function of adding your own custom POIs and sharing those places with your contacts. FourSquare isn’t always ideal or accurate in terms of an accessible service since that’s not what it is of course, but I don’t think there are many applications at this time that offer a better service than BlindSquare does.