Originally Posted by SticklerMac
Umm, one does magic damage one does physical damage. One penetrates armor while the other has to fight MR.
Why are you even comparing these items?
This is the same things as saying
"Bveil is superior to Sunfire Cape. They both give health, but bveil gives you the bubble."
The items have different purposes.
EDIT: Yep, downvoted by OP for pointing out the glaring flaws in his argument. This is expected.
You're downvoted because you can't read or you have no idea what the Last Whisper does.
Carries need Last Whisper to kill tanks and bruisers. They're the only ones who can reliably do it lategame because Crit+AD+AS overcomes all defenses if it has LW. Black Cleaver is too situational for me to get it much, except maybe on Corki.
It's a midgame item that doesn't scale well and requires me to attack something 4 times in a row to do full effect. MEH.