I'm not sure how it works in regards to UAC's as I don't actually know, or never seemed to notice, if that weapon or other AC's have a significant amount of knockback compared to missiles.
Speaking from experience however, when getting constantly barraged by any sort of knockback weapon (including ppc's), it practically impossible to line up an accurate shot for the duration of the knockback effect. It is possible to land hits, and depending on your luck and ability, they can be somewhat accurate, but for the vast majority of situations, you wouldn't be able to do any sort of serious damage. There's no external visual indicator to show that the mech is actually being knocked around; the effect is inherent only in the recipient's cockpit.
This ability is what made a well piloted 0.2.0 Vulture B nearly impossible to kill one-on-one if it was in range of you, as properly chainfired, there would be no break in the DSSRM stream, and as such, the knockback effect wouldn't really end, and you could never land an accurate shot. I'm not sure how it performs in 0.3.1, but I imagine relatively the same, though I haven't seen it very often.
So short summary: It's damn hard to line up a shot while under the effects of knockback, and you're more likely to spray your fire everywhere.