Information Week has a good essay in How To Choose The Best Linux For Your Business. What sets this one apart is that is provides useful categories and classifications for both distributions and support mechanisms.
Distributions are separated into subscriptions, community maintained, and the Ubuntu halfway model. This is different than other schemes such as the update mechanism used by putting the focus on how you will balance system management between what you can do and what you must purchase rather than how it works.
Most companies, however, will want to pick a mature, respected Linux distro with a solid track record. As a rule, these distros fall into one of three categories. Two of these categories involve Linux distros that are associated, in different ways, with a specific corporate backer; the third category includes community-developed Linux distros that have stood the test of time and enjoy a stellar reputation among business IT users.
It is noted that the Linux support system is robust because (a) those who provide support do not have other distractions in their business model, (b) the barrier to entering the support market is very low, and (c) there is abundant community support. This means you can choose what kind of support best suits your activities and needs but are not bound and dependent upon that choice.
A business usually looks for software that provides a business function. An individual may look for software for self education. The theme of this advice for choosing is towards the function and its necessary support. That is a point of view not often discussed in this context.