I have two Tablo units.
A new 2 tuner 64gb, which died 4 months in and then was factory replaced. While I was waiting for the replacement, I ordered a refurbished 4 tuner (Black Friday 2017) and then added the lifetime guide membership.
The only benefit I see on the new 4 tuner Tablo unit is the 8GB flash. So if the Tablo firmware needs the extra flash in the future I will upgrade. Or if my 4 tuner pukes then I’ll wait for a refurbished new version of the 4 tuner unit.