I'm not yet large enough to get either of these yet but I was wondering which is best for an attack build?
Okay. Abyssal is 10% of your stats and lowers with your troop count. Ie: 4mil attack stats bta = 200 mil raw x 10% abyssal bonus= 20mil bonus to attack stats. But, at half troops, you drop to 10mil bonus to attack stats. And that is the same as the feather at lvl 4. So, below 50% @ 4mil bta attack stats, the feather is better, above 50%, the abyssal is better. The sickle always sucks no matter what.
Sickle is exclusively used during osw stripping, as it doubles the amount of gold lost by your victim per strike!
Contrary to popular belief, the abyssal sword does not decrease in power when troops are lowered. It also does not count other static bonuses (other equip, allies). It solely takes 10% of your max attack power and adds it, it never deviates or changes. On a side note, the feather is better until your attack power is greater than 50mil, and the sickle is the worst of the three and is only needed or a certain eb (same with the abyssal sword but that sword also isn't useless). I personally choose the feather because Im a hansel and the feather gives more attack power than the sword. Hope this info helps