closest Space/Ultratech equiv to the giant power armors used by Marines in Starcraft?

[Tyneras]

DR (Ablative (Cutting Only)) would model armor that resists most attacks but gets worn down by the zerg rush.

Another build I've considered is layered DR of:
DR (All or Nothing) Enough to resist small arms and the like.
DR (Ablative or Semi-Ablative)

I like the second one since it works for a lot of situations where you want armor to be worn down reasonably quickly, but not by attacks that are below a certain threshold.