HWM definitely read Randomizers better. Since programs sample at different times, best way is to compare is max temps under load, they should all be nearly same.
Coretemp and real temp max load are both 68, 68, 68, 66. HWM is 67, 66, 67, 65. Mine is 3-4C off, guy on OC was 2C off, randomizer is 1-2C off. Interestingly, I put my pc back to stock, then HWM was only 2C off at load on 3 cores, 1C off on 4th. Then OCed to 4.55 all were off at least 4C with HWM at load.

Randomizer, can you try OCing your cpu and see if error increases while overclocking like it did on mine.