It depends on your skill level, and that of your guests
IMHO FWIW of those machines listed in the poll, in the order I'd recommend
SW
A fast, and sometimes brutal, game.
GB
A drain monster likely to frustrate lesser players, but with new code coming who knows what it'll be like.
GoT
Some of the call outs are fun, and if you have watched the series it ties in well. Despite all of the houses better players will stick to Greyjoy or Martell, I've come to find it a bit boring having only had it for 3 months.
ST
Easy to understand - hit the flashing shots, but all of the modes are similar.
AS
Toybox is a clever toy. Very different shot layout to any of the other machines you've listed and is getting new code
Met
Great game, with excellent callouts and lightshow. Lesser players have 4 easily understandable MBs to go for, better players have the CIU modes to go for.
TWD
Fantastic game, easy bash toy for lesser players to get MBs, deep enough to survive in a single pin collection for a great player.
GotG
Same layout as Met, brilliant soundtrack and video clips. Great bash toy with Groot. By far the most polished code Stern have released recently. Easy for lesser players, deep enough for better players. Great game all round.
So GotG would be my choice