mostly only buy digital on xbox one, physical on ps4. I feel i will be able to go back on my old purchases down the road more with MS than Sony at this point. I am also an elite gamestop member and get decent discounts on used games which is a big portion as well for physical purchases.
plus for digital, 99% of the time, i wait for a gold discount or sale, its so rare I buy full price digital, only Halo and Gears games I do that with.