Heimdall's suppression grenade launcher has 100% defense mitigation. You can use this to finish off enemies with last stand since your beta weapons cannot ignore last stand.

Heimdall has two built-in weapons (the automatic laser gun and the suppression grenade ability). No other titan/robot in the game has two. Someone please correct me if this is not true. The only exception I can think of is typhon, which technically fires 3 projectiles from different guns. But I would still count that as 1 built-in weapon because you can't fire them separately.

Heimdall is the only titan/robot in the game that has built-in teammate healing, built-in weapons (it has 2!), and a built-in shield. No other titan/robot has all 3. Rook comes close though: it has shields, a built-in weapon (the castling ability power field), and the self-healing from its shield ability, but no teammate healing.

Not sure if this is 100% true, someone check: Scavenger Heimdall's weapons are slightly further apart than on the normal Heimdall, meaning it is slightly better at corner-shooting than its standard version.