Bastion or Transistor ?

Both.

If I had to pick one to play first, it would have to be Bastion. Everything pretty much everyone has said is valid: they are both great games, and either one of them would be a great purchase. However, I think Transistor is even better for having played Bastion, and I'm not sure that benefit would work the other way around. I know it might sound silly, but I think Bastion is a better introduction into the style of these games. I feel like Transistor feeds off of the foundation that Bastion builds in a very subtle way. Playing Transistor before Bastion would feel almost like a step back when you get to Bastion (in my opinion, as this is a very subjective feeling).

Both .

I choose Both and i played them on PS4.

Finished both and enjoyed Bastion way more without a doubt. Better in every regard so pick that :)

Bastion better story and action

As some would say; Bastion is the better experience, while Transistor is the better game.