Its bundled with some of BT's business internet bundles. A couple of my customers tried it, didn't like it
The issues were
speed of file opening / saving over internet
problems in understanding the concept, leading to problems in file handling (i.e. trying to understand "saving in the cloud"
managerial resistance to storing files off-site (Security)
real reluctance to "rent" software rather than purchase it
reluctance to trust M$ with company data
Same objections applied with other customers to Google Docs