I think ( think ) FastDL is meant to be faster - one as you said you can strip out content you don’t need, but also I think your own web server ( dependent on host ) will be faster then Workshop.
As for easier for devs, workshop is IMO much easier to update. I just shove it in a folder, load a program and click update. Rather then having to individually upload to webserver and add into lua as a resource download.
You make some points. But it all depends on content.
Workshops download-speed IS faster than FastDL but FastDL limits the download-size.
It all depends on the distance to the FastDL host, and steam got servers scattered around.
It completely varies on your location and distance to the server and if your using some cheap free webserver pumping out a single mb a second at best to players which are really close to it, or having an actual dedicated server or even VPS on a 100mb/GB port being able to provide a faster speed on a more global scale. But that is a pro to workshop DL, it downloads on the nearest steam server to you.
We can talk about every small silly detail; that really don’t matter much. (What I’ll call flyfucking. :P)
I would say that the workshop is best.
While it is a bit buggy, goes down now and then and requires the client to download a few extra kb. It is easier, up-to-date and free.