It has been handy against the Romulans, no doubt about it. I did switch though to a + Phaser Weapons console when I hit Commander though on my science vessel, and if I can't manage to pop a plasma torp with one of my three arrays, my shields can handle the impact pretty nicely. I think it has kinda lost its usefulness at this point, but beforehand it was awesome. ^^
I didn't find it all that usefull. I seemed to only attack 1 mine out of the 5 that come. What I did enjoy was getting up close and personal to the enemy and having it automatically attack them for me.