As far as I know 662 resistance equals to 1% damage reduction. Brass would give me about 8000 resistance which would equal to about 12% damage reduction. The set also adds an extra 1000 hp on top of the resistance.

Plague Doctor has 6000hp on it so the question would be what is worth it better for pvp, 5000 extra hp or 12% damage reduction.

The fact that Resistance is additive with other Resistance means that the added percent mitigation is generally more effective than the equivalent percentage that's applied multiplicatively. The fact that bleeds, Corrosive, and Onslaught exist push you towards some percentage based mitigation as well.

That said Fortified is certainly more effective than Plague Doctor unless you're doing a specific max health build. Fortified is probably at its best in NoCP.

Mark of Pariah set does look nice and below 66% hp it overperforms Brass. I will look into it.

Depends on the rest of your build.

Fortified brass and mitigation is good, but the 3 and 4 piece set bonus’ are subpar.

If you want to be tanky and have a lot of health % heals then plague doctor plus high resistances is better. If you have low resistances then plague doctor won’t be good.

I’ve found the best sources of resistance are protective traits, 1 piece monster set bonus’, and blood spawn.

As a warden with easy access to minor protection I’d stick with plague doctor. Plague doctor, blood spawn or pirate smelly monster set, 30k resists should be easy.

The difference between survival by having more health or having more resistances, is the ease of healing. Ask a healer sometime how they feel about the 60k health 20k Resistance tanks. A 42k Health, 33k Resistance tank is just as tough.

OP, I'd suggest downloading Tay's spreadsheet and testing a few scenarios for a noCP environment.

https://forums.elderscrollsonline.com/en/discussion/383840/math-pvp-defensive-set-comparison-impreg-brass-pariah-riposte-more/p1

Sets that provide the 2/3/4 pc bonuses as physical/spell resist feel a bit weak when you can double dip with monster set 1pc's and protective Jewelry.

If you are comparing Fortified Brass to Pariah, people underestimate Pariah because of the 5pc when it works a bit different than you think.

https://www.reddit.com/r/elderscrollsonline/comments/87gx55/daily_set_discussion_mark_of_the_pariah/

Top comment: "This is one of the best pvp pair sets in the game and so many people are oblivious to it. It offers a base 2700 Spell and Physical Resist at 100 percent health along with it's other bonuses. On top of that it increases as you lose health surpassing Fortified Brass Below 66 percent health. The set has Healthy, Arcane and Robust Rings which allows you to maintain high stam or magicka pool when pairing with light/medium armor sets. In PVP it can negate a players entire pen value and still leave you close to hard cap. I cant stress enough how great this set is and if you pair it with undeath from vampire....Priceless."

I tested it at 1 point and I think it was true, even if the scaling was perfectly 100% to 1% for the remaining 8394 resists, it would be stronger than Fortified when your hp reaches 70%. So it's win-win imo. That being said, bleeds are so strong. Wasting an entire set on resist felt underwhelming when I tried it. Your better off with a dmg/sustain set combo with monster set or jewelry for resists.

In a no CP PVP Fortified Brass is great. Craft it in medium armor to take advantage of juicy medium armor passives. Great damage, sustain, and resistances for a stamina build.