Yeah, I've got a Firecube for streaming.
I was looking at this as a player to DL movies onto a hard drive and plug into so that I can get true 4K video, rather than compressed streams or buying a UHD player like the Panasonic DPUB 9000. For 200$, it doesn't seem too bad.
I agree with
@panteragstk on this one. If I were you, I would start by trying Plex first. If you haven't downloaded ANY content yet, then that's a starting point. You are going to need to download a couple of movies. But, once you've done that, it (literally) takes thirty minutes to setup Plex on your PC, and download it to your FireTV product.
There are a ton of videos online which show you how to install Plex, if you want added information, but the first time I did it it walked me through everything. I already had a folder with some movies in them and a separate folder with TV shows in it. The program had me create an account, then asked where I stored my movies and asked where I stored my TV shows. Then it was done and ready to be used. I went to my Roku, downloaded Plex, and logged in using the same username/password I created for the account, and I could immediately playback my movies.
COST: FREE!!!
That was a big thing for me. That I could try it out in my home without any cost to see how I liked it. It was SUPER painless to setup, took maybe thirty minutes, it cost me absolutely nothing, and I was done.
The downside? You have to have a computer available to store the movies and TV shows on. A product like the Shield can perform this duty, but in my home, I had an old PC from 5+ years ago I was using on my original Plex server. I just moved it all to a much newer computer, but I still keep that computer on and running full time to act as my Plex server. It works well for this duty. If you have an old laptop or computer, you can use that for testing out Plex.
There are a TON of videos online about setting up Plex, requirements for using Plex, etc. These are tutorial videos and give you different options, because Plex offers a ton of options. You aren't as hardware limited/locked as you are with a dedicated unit like the EGreat unit. The videos are often very helpful. The software setup videos are great because they are typically about 10-15 minutes long and really show how easy the setup is.
I'm not sure how computer savvy you are, or are not. Skills vary wildly from person to person, but one thing I hated with my DuneHD media servers was that networking to them and setting up network shares for hard drives was painful. It was kind of a 'skill' they just expected people to know how to do. I did not, so it took a fair bit of research to figure it out. So, if you get the EGreat, you need to figure out how you are going to get videos from your computer to the hard drive attached to the EGreat, or you will need to figure out how to map your computer's hard drive to the EGreat. It can't just 'discover' the hard drive on it's own. Unless you use a USB hard drive, in which case you may be physically moving a hard drive back and forth all the time, which isn't convenient at all.
This is why I love (LOVE!) Plex and why my family does as well. I sit in front of my computer, I download a video to a hard drive that is inside my computer, Plex sees the new video file, updates the library, and the Plex App on my Roku, whether at home, or ANYWHERE IN THE WORLD, can now see that new video file and play it back. My brother has a Roku at his home, and he can watch movies there. There is one in a vacation property several states away, and we can watch movies there. It is incredibly easy and convenient to use... and reliable.
I won't say I haven't had any hiccups, but as I said, there are a TON of videos online and most are really helpful.