VIM2. I got it because it has a supported Sat dTV board. However when the cost of a sat board, power supply and various other bits are taken into account it worked out at around €100.00. If I were to do it over again I would have gone with the MeCool KIII or KII which does there same job in a nicer package. I was sucked in by claims of excellent Linux support which simply wasn't real with the Khadas VIM2.
Still, as I said if I had the decision to make again it would be for the Vorke V1+ at €140.00 with an external SAT>IP box for sat duties.
Not much help to your use case I know, but I would be very cautious about going down the S912 path for what in reality will turn out to be no better performance than any of the S905 options.
Shoog