It is the most fun RTS there is.
Not the most skill dependent, or complicated, just the most fun.
I find it more fun to turtle and make fuckawesome bases and patrol routes personally, but that's just me.
Any RTS that rewards turtling and having intriquite basebuilding? I really liked making units patrol an area in a good group, or having walls surrounding my bases with the entry being guarded by a pillbox or a pair of deployed GIs.