User blog comment:Tyrant Belial/Feral Flare tests/@comment-4636093-20140407152036/@comment-1330314-20140408110926

Gunblade's active has a passive component, Reload, which reduces the active's cooldown by 3 seconds every time you land a single-target spell or autoattack. The AD the item provides is nice, but not as good as the AD or on-hit damage you can get from other sources, and the AP by itself basically translates into mediocre amounts of extra tankiness and damage, effects you can significantly improve just by getting straight-up tank or damage items. Though slightly more expensive, Trinity Force outclasses it on Skarner in pretty much every way, bar the sustain.

The thing with Feral Flare is that its stacking on-hit effect means that, even as you buy damage items, its clear potential will outscale that of any Spirit Stone item. A SotEL coupled with a few damage items will let you clear the small camps in a couple of seconds, but Feral Flare does that on its own, and fairly quickly at that. Moreover, the on-hit effect is massively more effective at clearing the larger camps, and can reduce clear times by an order of magnitude, to the point where you can solo buff monsters you wouldn't be able to handle with any other jungle item. With a moderately stacked Feral Flare, a Blade of the Ruined King and boots Master Yi can solo Baron at levels 14-15.