Yet another question on IGOUGO vs Alternating Activations

I'm developing a tactical cyberpunk skirmish game with 6-15 models a player. There is a dynamic reaction system similar to Infinity or BlkOut or Heavy Gear etc, and uses an Infinity-esque order pool (you can activate the same model multiple times in a row).

My goal is for gameplay to be fast and punchy, with the feel of momentum swinging back and forth between players by activating successive units or interrupting your opponents turn.

So in this context, and in general, what's the difference between Alternating Activations with the opportunity to activate successive units, and IGOUGO with lots of opportunities to interrupt an opponents turn