Both looks poorly constructed
open up a panasonic and you will be more relieved with the protection mechanism.

if you intend to use tank type, make sure make sure make sure you install additional elcb of 10mA non negotiable.

i used to try to supply to panasonic's water heater for the elcb. the QC is extreme stringent as they reason out, its due to safety. 99.99% is not good enough for them, and that 0.01% will mean someone die from electrocution.

and my product is not the cekai one like u see in pensonic and alpha.

and yes, after looking at many brands internal, I would only bet my life on Panasonic water heater.

if u own a landed property, go for solar. or, go for gas water heater.