I'd say yeah. I wasted money on a fair few so called high spec "Android Tv boxes" but non of them lasted more than a year or 2 before they became buggy.... slow and the majority were never supported by the manufacturer's.

So I finally bit the bullet and got the Nvidia Shield 2017. Best money I've ever spent. The unit is nearly 4 years old now and is constantly updated by Nvidia. Even the 2015 model is still supported! Mine gets used for streaming my movies off my NAS which are a mixture of 1080p 4K and 720p. All work great. I only recently purchased a 4k TV this year and I'm now enjoying watching 4k hdr Netflix and Disney + all streaming from my Nvidia Shield. It's also my Plex server and quite happily pumps 1080p and 4k movies to my 2 firesticks upstairs. If my Shield ever broke it get replaced straight away.

Given your setup the upgrade might not be as noticeable as you might want unless you like snappy interface. I have the same setup as you and I bought a Shield 2019 over the weekend for my projector. This is in anticipation of an upgrade to 4K although content wise 1080p remains the majority of my content today. I still have 720p contents. I have a Shield 2017 attached to my 1080p 10y old Samsung TV in my bedroom. I tried to replace that with a 4K TV with AndroidTV built in and well it lasted less than 12 hours before going back to the store. I literally hate technology transitions given all the BS manufacturers pulled due to the never ending technology evolution. It will also depend on the Apps you use. Plex server is built in on ShieldTV although I don’t use Plex but Jellyfin. Finally, it will depend whether you want to upgrade your audio system too in the future.

I have two Mi Box's and one 2019 Shield Pro. The shield pro I use on my LG C9 OLED. The Mi Box's I use on my 1080p TV's. Both do their job.

The shield on sale right now for $179 is a good deal but for 1080p, it's just not worth buying over the Mi Box that I already have.

If you already have something, don't upgrade to the shield. If you have nothing, go for the shield because eventually you'll want to upgrade to 4k and the shield is on sale right now so it's the best time to buy one.

By the way.. don't buy the tube. Get the pro version if you get a shield. Lots of people have issues with the tube with 4k content.

It's worth it. Not because of the upscaling, but because of the shit I don't have to deal with if I use anything else.

I have 2 Mi Box 3s and 2 Shield TVs. Honestly I don't notice much of a difference between the two. If money's an issue, just stick with the MiBox 3. My $.02.

You have the mi box 3 global, which is the only cheap box besides shield that can passthrough hd audio if you stay on android 8.

The only difference will be GUI speed and upscaling. The first one doesn’t matter when movie is playing and second one only matters if you have 4k tv playing lower resolution media. My tv does the upscaling from 1080p to 4k and does great.

In other words my mi box plays remux file just fine off external hd

I have 3 Shield Pro and one $50 Chromecast Google TV ... give the Google TV a try... order it from someone that will let you return if you don't like it... Google Updates are important

I've not got any experience with other Android TV-boxes, but bought a shield for my GF some months ago, and even though I don't have 4K I bought one for myself recently because it's been so trouble free for my GF. Plus the triangular remote is really good, and addictive to just hold.