I tested out perfect steel armor vs perfect Military armor, min maxed with heavy/light armor perks, banded armor plating mods and customized fittings and 3/3 rule 1 cardio (found max armor values from XMLS)
Max Light Armor= 12.2 Armor/slot
Max Heavy Armor= 16 Armor/slot
16*5= 80
5*12.2=61
Add 5 banded armor plating mods to each (+10)
90 DR (HA) vs 71DR (LA)
Perfect Heavy Armor(Steel):
10.11 Stamina Regen a second
92% movement speed
90% Damage reduction
Perfect Light Armor(Millitary)
12.64 Stamina Regen a second
109% movement speed
71% Dmg reduction
one thing to note with this is that 71% means you take 29% dmg, and 90% means you only take 10% dmg
so you take almost 3 X as much dmg with max Light Armor vs Heavy Armor
you also regenerate stamina 25% faster with Light Armor
one thing to note with pain tolerance is that it takes place after you get hit
so whats happens with 5/5 pain tolerance is you take the max damage, and then are immediately refunded 25% of the damage you took
so if you got hit for 20 dmg in HA you would take 2 dmg and get refunded .5 hp and would take 1.5 dmg
if you got hit for 20 dmg in LA you would take 5.8 dmg and get refunded for 1.45 hp and take 4.35 Dmg
I think Pain tolerance is much more value for light armor, but every bit helps
TLDR: If you want to tank up and take no dmg and be lazy and not move, use heavy armor, if you want to be agile and quick and never run out of stamina, Use Millitary armor