well if the augment scales with duration, its quite good, sinde if you build for a polarize build (which effectively shreds armor) you should have about 150-200% duration. so thats about 7.5m/s*5s*150% -> 56.25m radius jammed weapons or disabled corpus for 6 seconds, which isnt that bad at all.
but true, now that i did math, 7 seconds do sounds fine though ^^
As to infested...mag is useless against infested anyway, right? polarize does nothing, crush isnt that stron against them, and pull is...well its pull. Magnetize is just "single target", so not really that useful against infested either :/