As previous user told, redhawk is quite close to SPICE simulated values. Next comes Encounter Power System (from cadence).
A Big no for Primerail + PTPX combo at this point of time, as we have scenarios where the tool is unable to understand some of CCS constructs in .lib itself.
I hope synopsys fixes it soon.
u can still , get away if u are running static IR drop, but Primerail + PTPX combo is very very pessimestic , u will end up overdesigning your Power Ground Network