My friend owns a Ducky and Rosewill keyboard and he says it's sad that the cheaper keyboard (Rosewill) feels nicer to type on.
And Filco is better than Rosewill so therefore it's safe to assume Filco will feel nicer to type on than Ducky.
That and I own a Filco too. It's the standard for solid construction no gimmick keyboard.
So the question is if you want a good solid keyboard or if you want pretty lights.
I think that you're not considering them fairly at all. First of all, all keyboards with plates feel extremely similar if not the same. Case construction might change that, but everything that isn't a Korean custom is plastic anyways. From all of the reviews I've read, the Ducky is always mentioned as very high build quality, quite heavy (whether this speaks to the double-layer PCB or just better case construction, I don't know), and the Ducky Yellow which recently came out has very thick PBT caps, much better than the often-complained-about thin ABS on the Filco.
Filco really doesn't live up to its hype. With Ducky, I don't mind paying $140 on a keyboard because it has solid construction, developed lighting, which actually took a lot of research, and is customizable. The Filco, in comparison, is a barebones, featureless keyboard; the same as a QFR, but at over double the price.
A better comparison would be if you want a tank or an Audi. Both are good choices.