Hello All,
First timer here. The new (as I believe) HDHomerun Flex has the USB storage option. It advertises there is no need for CPU or NAS. Will Channels Plus DVR service work with only this device or do I still need a separate computer? And if I do need a separate CPU does it have to be dedicated and always on?
Yes, you still need a separate computer that is always on to use with Channels. The hard drive products from SiliconDust will only work with their own DVR software. No other software can make use of the drives in the Servio, Scribe, or Flex.
Thank you for the clarification. I'll try not to haunt you, but your quick answer is perfectly comprehensive! So,,, Do you find Channels DVR to have enough advantages over the SiliconDust DVR service to justify having a dedicated computer and NAS?
Remote Access ... Advanced Pass .... Comskip ... Import your own shows ... too many to remember.
IMO....There's no comparison between SiliconDust DVR vs Channels. Channels wins hands down. SD makes great hardware, not sw. UI is not good..
Channels has so many options and features and they constantly innovate and it's the best TV experience I've ever had. I had SD DVR when it first was released. I literally boxed it back up less than an hour after getting up and running.
If you want a boring DVR and are okay with a no frills dvr, SD may be fine for you.
OK, I'm sold on Channels. Can you recommend the other hardware I need (CPU and NAS I guess) to pair with my HDHR Flex to get the most out of Channels DVR without breaking the bank?
Some use a PI .. ShieldTV mini PC ... NAS
You might want to start here ...
Channels — Channels DVR Server (getchannels.com)
I personally use an old mini PC. Its processor is 6 generations old, but it still has more than enough juice to handle multiple media servers, as well as several home automation hubs. I've found the Gigabyte BRIX line to be a great combination of power and value, and more than suits my needs.
Would you like to watch remotely on the go? If so how many people/ devices would need to do that at the same time. A raspberry pi would probably be the most budget friendly but I would recommend a mini pc or even a desktop. Commercial marking comskip runs way faster on pc.
Depends, how big is your bank? 
Many of use a Synology NAS. Mine has two mirrored 4 TB drives for 3 TB total storage after installing the system and Channels DVR server. And the Channels DVR client app for Apple TV is probably the best but I use Fire TV and Android devices.
I love my little Gigabyte Brix PC. It is an i3 Skylake model. It has been great for every day PC use. I don’t use it with Channels. I use a Raspberry Pi with Channels. Works great.