Part of the reliability question has to do with how insulated is the primary host site to outage due to loss of power or natural disaster.  Do they have a backup site and if so, where is it located in relation to the primary site?  I ask this question from personal experience with a provider whose secondary site was several miles from their primary site but, as it turned out, on the same power grid.  When the primary site was without power, so was the first and neither site had backup generators!