People who bought old Mac Pros (that really need the parallel performance and didn't just switch to iMacs during the long redesign lull). Developers might care

People who bought old Mac Pros (that really need the parallel performance and didn't just switch to iMacs during the long redesign lull). Developers might care about things like internal expandibility & detailed cost/performance ratio, but generally the overhead of switching OS in the pro space is heavy and in my (research IT) experience people are wedded to a particular platform regardless of individual gripes.