if your going for the t10 4 set the best set up is 4set+pillars. even with acsess to 277 gear I believe that the pillars are still BiS just because of the EH they provide.
The Pillars are BIS for all fights except LDW, Sindragosa and Lich King. For those fights you definitely want heroic Lost Hope, they have the most stamina of any legs. T10 heroic are bad compared to both pillars and LLH.