I'm finding a lot of conversations on what hardware can be used to actually run the DVR server end, but I don't see a lot of talk on what the best devices are to park next to a television to just deliver media from the DVR server to the TV over the network.
I'm looking for a mid to high performance device that would give a very smooth user experience at the TV end, and deliver 5.1 channel audio at the same time (via HDMI preferably). What do you recommend?
I use Android devices Prefer the Shield but the FireTV4K also works using software decoding on the FireTV 4K. I use both.
I like the idea of using the Shield, something that has some processing power. I don't mind spending a few bucks on something nice as long as it provides a smooth user experience. It's also an advantage if it has a fairly robust remote. I'm not a young guy anymore and I don't appreciate the remotes that don't have the conventional button controls.
Edwin, I seem to recall your name from SageTV forums ... maybe I bought an extender from you or something, yeah, I think that was it!
No but you know me as NYPLAYER 
The Shield might be dropping in price as there might be a newer one released this year.
Ah, yes, NYP. I'll keep my eyes open for good deals on the Shield.
The Apple TV app is our flagship product and has the most development time invested into it. That's what @maddox and I use at home.
Are you using the Apple TV app on an Apple hardware device of some kind at the television? I see reports of the Apple TV app being available at some point on;
Samsung Smart TV's
Sony
LG
Amazon Fire TV
Roku
The hardware is called Apple TV:
Am I required to login Apple to use Channels DVR on that device? Are there 6 whole buttons on that remote?
I use the NVidia Shield to run Channels, but I'm not a fan of the tiny remotes all the TV boxes come with these days. I have a Harmony hub with one of their remotes and that combo can control everything (shield, PS4, projector, amp, etc).
I've used Amazon Fire TV Gen. 2's and Xiaomi MiBox S'. Both have worked "ok." Avoid Xiaomi MiBox 3's if you see them for sale anywhere. They were plagued with problems. Also I believe there are still issues with the Amazon Fire TV 4K.
I'm thinking my next device will be an Apple TV. If I like it I'll probably eventually replace everything with Apple TVs. Don't care for either Google's nor Amazon's invasiveness.
I have 8 Apple TV's. 4 are the Apple TV 4K after replacing and/or adding more 4K TV's. We are very happy with the Apple TV's. Not just for Channels. Some do not like the remote but we do.
BTW... Regarding the new Apple TV "App". I am not a fan. I am interested in the new Arcade App coming in the fall for my grandkids.
You do need to create an Apple ID to use the Apple TV. Just like how you need an Amazon account to use the Fire TV, and a Google Account to use an Android TV (to use the play store to get the apps needed).
The Apple TV has been the best experience for me. I agree, I hate the remote...which is why I don't use it. You can pretty much use any universal remote for streaming devices I use this one for my Apple TV:
Which also allows me to control my TV a lot easier.
Does Apple TV still only have limited access to Prime Video where you cannot access bought movies or even rent or buy movies through Apple TV. In our household we need full access to Prime Video.
The Shield gives full access to Google Play , YouTube, Netflix and Prime does apple TV also supply full access to these ?
I'm not aware of any restrictions playing back already-purchased videos. I think the only restriction is you can't buy the video on the Apple TV itself -- instead, you'll have to buy it on Amazon.com from a phone or computer web browser using the same Amazon account, and then start watching it on the TV.
Videos included with your Prime subscription "just work" with no additional steps required.
The Shield is a great device, other than the remote volume control which is absurd. I've replaced it with a third party blue tooth remote with a conventional volume control and it works great for my uses.
The Channels experience is very good on the Shield, but there is some room for improvement where some functionality is not working or limited. The developers really should spend some time bringing the Android client up to feature parity with Apple TV and then some. I prefer the Android ecosystem to Apple as I'm sure many others do too.
Yeah I will Stick with the Shield it Provides everything we need I want full access to Prime Google play etc .. on my TV without having to reach for my Phone. I use a Caavo remote which I got from Amazon I too hate the Shield remote.
First, to the OP, go with the Shield for the use case you described. Sounds like you made that decision.
Now I’ll leave this longer review of the various devices that can be used as viewers for Channels. I’m running multiple versions of the major devices at my 6 different TVs, let me explain why I like certain ones for certain situations, and you can figure out what is best for you.
First, don’t bother with the cheaper versions of Apple TV, Fire Stick, or Android boxes. Performance is better on the more expensive versions and the cost difference is insignificant compared to that boost. So Apple TV 4K versus Fire Stick 4K versus Nvidia Shield. I use a universal remote (Harmony), so I ignore button placements but the remote functionalities are key differentiators.
Channels app experience: I find the quality on all three devices is close enough to identical. All are very good, no complaints. Go wired gigabit where possible. It’s just a great app with parity on the platforms, kudos to the developers. The only difference worth mentioning is that the Nvidia shield has additional keyboard functionality in a universal remote, so my wife can use channel up-and-down and guide numbers. This is the reason that the shield sits on the two tv’s that she uses; she missed channel surfing. This was what allowed her to give up Windows Media Center for Channels. As much as I like the Apple TV, the limited remote buttons mean it takes more clicks to do what I want. (If anyone knows a way to use Mac keyboard shortcuts to do things here, like I use Harmony with a Mac device impersonation to give me bluetooth volume control on the ATV, I’d love to know how.)
Now to the differentiators when you get outside the Channels app; this matters and will define the right box for you based on the other things you do besides Channels. The Apple TV 4K is for the TV that my kids use most. The interface is clean, it has the best apps that are most updated, and it is simple to use. The Shield is still at the TVs for my wife, because Channels is the only app she uses. There is a great home screen layout with customized channels where the top line when I turn on the device shows all my favorite apps in a line, and the second horizontal line is my Channels live TV guide with icons for every show in my defined Favorites order, and the third line is my Channels DVR content. From that front page my wife can scroll through her shows and click on exactly what she wants without even launching the Channels app. This is also simple and intuitive for guests, and allows a clean purposeful home screen centered on Channels. I know the ATV has something similar, but you have to choose TV OR DVR, can’t have it both ways. The downside of the Shield is that many Android apps are not updated so this is not ideal if for example you like Hulu or want the new Plex interface. Then there is the Fire Stick 4K. It’s fast and equal to the other two devices even on wifi, but the interface is a cluttered mess of ads, it takes too many clicks to launch the Channels app, occasionally Amazon installs other apps that mess up any Harmony automated launching, but it works well with Alexa for other non-Channels apps (which are updated frequently which is good). The main reason to go with the Fire Stick 4K is cost; it’s cheap and it works very well if you can ignore a cluttered view on the home screen. My kids don’t care but I do. I have this on all of my secondary TVs like at the treadmill.
If you use Bluetooth headphones, Apple TV is easiest, Shield is perfectly fine, but Fire Stick 4K doesn’t allow you to control volume on the headphones, so basically doesn’t work for that use.
For me, I only use the Channels app, so all of those differentiators don’t matter to me, so I like the device by the most comfortable chair. 
After reading quite a bit on the subject I have been thinking about switching my Channels clients from FTV4K's to Apple TV's but there seems to be contradicting information on the forum as whether or not the Apple TV decodes via hardware or software?
Do people find the viewing experience glitch / stutter free on an Apple TV with no framerate drops, just as you would expect from a traditional TV?
I am especially interested in how people in the UK are finding Apple TV's using a HDHomeRun as this would be my expect setup
Thanks very much