It's great on ADCs that are more skill reliant (Graves, Ezreal). I wouldnt build it on Caitlyn or Kogmaw or similar ADCs though.
Also Jayce+Ghostblade is core of his ADC build since he can turn it on melee form and swich and use full duration and since it's on-demand attack speed, it doesnt interfere with his hypercharge, which is reason you'd pick Jayce as ADC
Horrible item, it won't give the AD carry enough attack damage to be effective. Blood thirster is so much better just due to scaling. This item is only thought to be good because you are going against bad players. Any players who can actually play ad will be able to take advantage of you buying such a weak item.