We are using Raspberry Pi 3 B+ running Raspbian with the RPi DVB-T2 TV HAT.
We use the over the air TV guide (broadcast with the tv signal), so no internet connection or subscription are required. You can enable the OTA programme guide somewhere in the TV Head End settings.
I found that disabling the on board wifi and bluetooth reduced the occurrence of recording errors (don't know if is specific to Raspbian or if it also applies to other distros)
If you plan to do a lot of recording it's best to understand which frequency the channels are broadcast on. Each frequency can carry a number of channels (multiplexed). With a single decoder you can record a number of channels simultaneously if they are all on the frequency. If you try to record two channels on different frequencies simultaneously then one will fail. I have setup a favorite channels group of channels which are all on the same frequency. The ultimate setup would be to have a RPi + decoder for each mux (frequency) and network them together (we have two, one headless which does most of the recording, and the other connected to a 2k monitor for playback and occasionally recording channels on a different mux). I've set Raspbian to drive our monitor at 2560x2440, but kodi plays more smoothly at 720p (Kodi is setup to use it's own framebuffer at a lower resolution). Each TV transmitter will use different frequencies (to avoid interfering with other nearby transmitters) so which frequencies are used will depend on your local transmitter.
Keep an eye on your ram usage. We had a few crashes until I figured out that we were filling the ram. Logging out and back in frees up the ram (possibly there is a memory leak in one of the programs we use). Now they've been runing for >212 days without rebooting.
Also keep an eye on the RPi clock (time) as they tend to drift due to using a basic RC oscillator. The time is broadcast with TV signal but I think TV Head End has to run as root to update the system clock running under Raspbian. The recordings are controlled by the system clock so make sure that the time, date and timezone are correct.
I did our setup quite a while ago and haven't updated it recently so things may have changed.