It depends on your game and your target devices. If you are making a pixelart game, then you should use point sampling and upscaling. Your game and your assets will be smaller in size, and you put less weight on mobile GPUs. In the end it will run on more devices. On the other hand, if you don't want to go with pixel art, then I think downscaling would be better, because then you use higher resolution assets, so your game won't look bad on bigger screens (like 10" tablets). I'd suggest, in that case go with what BackendFreak said in the mobile resolution topic:
I personally pick an average resolution (1200x800) and use images of the 1.5x sprite object size. It scales nicely both ways.