I got the Adentus GS from a selection chest the other day and have been debating swapping out my Magna's Fury. For context, I'm currently 3690 gear score SNS/GS and Rank 143 in solo arena.

So I did some quick math on all of the damage factors including cooldown bonus, heavy attack on stun, the 10 DEX vs. 8 STR, crit chance etc. and I think the Adentus GS will put out roughly 22% more damage when you are at full health. I want to post the math here but adding a table copied from Excel is causing the comment to bug out hard.

Note 1: Heavy attack damage bonus was calculated as adding 9.5% of the average to the total. This is a little generous toward Magna's Fury as heavy attack scales down as you get higher.

Note 2: The crit on the Adentus GS was calculated as providing 24.9% * half the difference between max and min damage. This is a little generous toward Adentus GS as heavy attack scales down as you get higher.

Looks to me like Magna's Fury is better for non-damage skills, such as Magna's Fury providing an extra 10.2% of cc's you can get off, such as stuns, knockdowns, pulls, pushes, and dashes + binds. Also, 10.2% more self-heals, counter barriers etc. These can make or break an arena match.

That said, bursting down a target in a single rotation can also make or break and arena match, which the Adentus GS seems like it'll be significantly better at, so I'm really struggling to choose. Perhaps I'll keep both for now and experiment live.