It would be a more comparable measure to know if it heats to the proper temperature in terms of seconds.
The Hakko 936, and similarly the Fx888, will get to 350C in 40 sec or less. The Metcal 5000 in 6 seconds.
To compare your new iron, you need to be able to measure the tip temperature with some accuracy.
If you have any eutectic solder around such as Sn99.3Cu0.7 which melts at 227C, the Hakko 936 reaches that temp in under 20 seconds.
Just tested the Soldering iron. Not much you can say about soldering irons, but this one uses a Hakko element and tips. It seems to heat up very quick from room temp(a matter of seconds). This helps its rapid thermal recovery after each use.
The power supply volt meter seems to be approx 70mV from actual. Not too bad given the 100mV resolution of the display.
Regards