Asus uses a custom ASIC to support hardware monitoring. For awhile, they are the only MB manufacturer who supports on-die thermal diode on all their Intel CPU products.
The hardware is supported by the Asus PCProbe software. It has some problem when the fan control is activiated in earlier version. The problem has been corrected since version 2.03. The total number of functions are limited compared to Motherboard Monitor or CPUCool, but it is adequate for most users. The real time monitoring display is the best among the three mentioned here. I have never seen any different in the temperature, fan rpm or voltage measurements.
The hard/soft combination above is as good as any that I have seen from any MB manufacturer.