Tippy,
I’ve been using the Airtv device fora couple of years now. I can say that it’s easy to use and fairly easy to set up. I got it as part of a prepay for 3 Months for Sling and get the device for free.
I’m using the official Sling app to use it, and AFA I know you won’t need a sub to use it.
It’s great because we can watch OTA on all of our TVs without having to run but one cable from the antenna to the AirTV box.
For DVR, you must use hard drive. I just utilize a used 500GB laptop drive in a $5 encloser to do this & that works great.