

On GDI - Jumpjets (mammoths can run them over but multiple squads can still take one down without too much trouble), predators, mlrs with blockers, titans, kodiaks (testing these still this patch, they haven't been great in previous patches but I think the recent banshee and talon nerfs leaves a bit of room for them), sometimes I'll throw a few orcas at them combined with other things - orcas aren't really strong enough to take mammoth's on their own but they do great added damage, Titans also do good work especially when you consider you can get two of them for the cost of a mammoth pretty much, and every so often - talons, yes, really, mammoth aa is bad enough that I have killed mammoths with talons before :P On nod - Banshees, Infernos, Bikes (squads make bikes shockingly good against all slow firing tech units), scorpion tanks, Basilisks (rarely these days though, nod tech isn't often run), Kane's obelisk with some blockers in front of it.
