User blog comment:Deshiba/Circumventing armor for marksmen/@comment-1330314-20150520130106

Generally not, because you're going to want Last Whisper's damage amplifier immediately, even if Ashe's new Q applies full stacks of Cleave in one go. If you happen to have an extremely solid frontline (2+ really tanky champions) capable of providing tons of peel and letting you do what you want in the back, then TBC might be better, especially with an AD-heavy team, but then again that's not what Ashe specializes in (Ashe is meant to provide crowd control herself at the cost of damage), and if you have a tanky, AD-heavy team, chances are one of your teammate's a bruiser who picked Black Cleaver already. Overall, it's generally better to pick Last Whisper and have a bruiser on your team pick TBC so that you can stack up armor reduction/armor pen against the same targets.