Well, I see a lot of advantages.
Very simply said: If the opponents become more difficult, then the same things usually helps on the player side 
But honestly: Only because of acid? The frequency of acid opponents (my experience) and the acid damage (update) have been reduced. And even if they are there, you can only concentrate on the chiron and stay away from the arthrons. With my style of play NO problem at all, actually never had.
- Resistance to Mind Control, Poison, Blood, Virus is something …
- In a relative comparison: very good armor and still better speed and accuracy (poor stealth can be neglected in the armor, I personally think)
- But more importantly, the included skills
- The disadvantage is the higher acquisition and repair costs (irrelevant in endgame)
@etermes can probably explain it much better.
I stopped using these supertoys when I realized that they affect the difficulty curve exactly the opposite of how I would like it. With the DLC the early game is more difficult because I think the “Pure” is a difficult (but interesting) opponent. In addition, I can’t really afford the supertoys at the beginning.
But: In the endgame I literally swim in resources, I can easily equip the soldiers with the supertoys, which can make me even more effective (to make me even more bored).
But not a big deal: luckily I can just turn off the DLC.