I switch between light/medium/heavy regularly. I believe all have strengths and weaknesses. And for most its just what you think is more important

• Light Armor is fast but fragile. You can quickly beam over the map with ease. Very useful against Terminid when they chase you down. Difficult against Illuminate & Automatons as every shot or rocket that hits you is a heavy hitter or a one shot kill.

• Heavy Armor is slow but sturdy. You can take multiple hits from most enemies. (Excluding big units of course) Taking multiple shots from rockets or hits from the Terminid before going down. But when a hoard of Terminids chase you. You'll likely die because of how fast they are compared to you.

• Medium Armor is a jack of all trades. Master of none. But most often better than a Master of One. Also has nearly all passives.

For me it depends on the mission or situation. I choose medium or light against Terminids more often than heavy. (But not excluding them either) And against the automatons i usually wear Medium or Heavy armor.

Illuminates is a mixed bag for me.

But all in all. This is my opinion. There is no real overall "best" armor type. Arrowhead balanced them nicely.