I’ll +1 to Linux, however I don’t believe that Epic will move Linux higher in their priority any time soon. While Linux may gain a lot of traction in movie production nowadays, it’s far from it in Gamedev. And the more I read about it, the more complexity I see in M$ vs Linux problem, there are so many layers to it. And yes, there’s also Mac.
This is exactly the reason why I started looking into Linux recently. Well, regarding desktop. I’ve had about a year-ish of experience with it after building my own DIY NAS, and using Ubuntu headless to serve everything I need, including filesharing, web servers, even my very own Python voice assistant, working as a server-client app 
But recently I started looking at it more from Desktop perspective, even installed it on my wife’s laptop, my own and now I’m trying it out on my main workstation, dual boot of course.
Reasons were - it’s really hard to control what Windows 10 is doing now, even after all the updates. Weird CPU usage out of nowhere, when it tries to update something or doing who-knows what (and even if I know what it’s doing, I don’t need it). Constant updates, the idea of updates is good, but I wish I had more control over them. And while it’s OK on desktop, it’s compelte nightmare on my Surface Pro 1 and laptop.
It causes them to overheat, so fans work at 100% blowing out hot air when I don’t need it. And I can’t turn it off. When all I do is just browse something, WIn10 thinks “Perfect time to install a few updates.”.
Not to mention it’s reboots. No matter what settings I set, there is still a chance that Win10 will reboot at time I don’t need it to do so. And it’s really annoying.
So, with all that said, unless Microsoft changes their course of action, I see Linux getting more traction in recent years as Desktop OS. All new developments in it’s kernel, drivers supports that. And when it comes to it’s modern desktop environments… Man, I really love Win10 style. But KDE is gorgeous, and I love the level of customisation it gives. And if you don’t like KDE, you can always use Gnome or something else. You can even install Cinnamon and Win10 style on it, to make it look almost like Win10. I don’t like the amount of fragmentation there is in linux right now, but I love that it offers so much customization.
SteamOS is also a nice idea, and if it shows any progress… Well, SteamOS is essentially debian, if not ubuntu, from what I remember, so it could be a great start.
So, comparing Win10 and Linux, I do feel that Linux, once it’s working, is MUCH MORE reliable nowadays.
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As for downloading assets…**
I did not try it yet, but I think it should not be that hard. You can setup a project on a drive accessible both from Win and Linux. I do have separate RAID drive for all my work files and projects. So I would keep a project there. Then if you need to download something from marketplace, go to Windows, open that project, download whatever you need, and then when you get back to Linux and open the project there, it should all be in place.
I’m not sure about plugins though, but I think you have options there as well, installing plugins into project, or globally…