Hmm, I bow to others’ expert opinions about it.
My Davefab tank is an isolated sample, however it has been faultless so far and therefore I’m happy with it. I did need to fettle it slightly before fitting, and maybe this is what has made some people unhappy.
Some words and pics in this post below show how I fitted it without draining or losing any water;
I chose it above other metal tanks simply because it was black and it has a sight glass to indicate coolant level. When it is up to temperature, one can also see the coolant circulating past the tiny window.
I soon took off the sticky metallic label to improve the look in the engine compartment.