ADC Itemization

Bleh... so if i understand this correctly

path 1: Spikes earlier due to bork rush, does less damage until super late game

path 2: Spikes later due to shiv/ie rush being expensive. Deals WAY more damage early lategame

What makes you choose one path over the other(shiv is representative to all zeal deviations)? The adc in question is

If you dont rush bork for the early spike, does it still have a place in builds? Where? How much damage is that 8% actually... If im not going for the early spike it seems to me like certain items such as deaths dance ect might be better than bork due to the overall flat damage increase.