Are you actually going to use the new keyboard that you're buying or are you just a collector?
If you're actually going to use it then wouldn't recommend either of those. Most mechanical keyboards are relatively similar nowadays since their typing characteristic mostly depend on the switch and most are cherry anyways. After that is mounting (most are plate mounted anyways) and keycap materials (can easily be replaced)
The things that makes keyboard differ would be practical factor such as:
Macro/FN key binds and customizability.
What type of stabs are used.
Shape, such as the initial tilt of the keyboard without feet and amount of tilt with the feet out.
If the connector cable is detachable.
Where the connector leaves the keyboard.
An IMO important thing amongst the above is how some keyboards have paths on the back which allows you to decide where the cable exits the keyboard.
Neither the FILCO nor the Custom has this. Therefore I wouldn't get either.