system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40K] Was The Emperor's power armour special in any way, other than the fact that The Emperor was wearing it?

Did it have any special properties other than its colour? If you were to compare it to the latest model of power armour, how would it fare?
gpt
It is either the best armor ever created or the worst armor ever. 

The Emperor was a big tinkerer and loved to build and develop new technologies. It is very unlikely that he was wearing a mass produced armor and its was probably created by himself for himself. Considering we don't understand most of the technologies he created, it safe to assume his armor followed suit. It is probably still well beyond the highest tech the imperium has to offer.
      
On the flip side, it could have been completely ornamental and the Emperor's true armor was his psychic power and intelligence. This made any armor void and unnecessary. Granted he did get killed by a mortal blow from Horus, but this was due to him dropping his guard thinking he could save his fallen son. 
       
Either way, he also loved not telling people about what he was doing with his work and things were on a need to know basis (Horus and that golden throne thing). So he probably wasn't too quick to tell people about what his rolling save was on his armor.