This depends so much on the room environment. Not super up to speed on the Sony but I don't think it has lens memory. If your in a dedicated theater with full light control and dark non reflective surfaces the Sony makes more sense. A 2:35 screen lens memory is almost a requirement but not an absolute necessity. In a poorer room the Epson extra lumens could be a benefit. Screen size and seating distance is also a factor as too small a screen or too far of a seating distance the difference between true 4K and half 4K is irrelevant.
"Smart enough to know better, to old to care" ------ Dedicated Bat Cave Home Theater, JVC RS49U/Mitsubishi HC7900DW Projector, 110" 16:9 Jamestown screen with variable power masking for CIW 2.50:1 to 16:9, Marantz 7009 with 7.1.4 Atmos with Ohm mains,3 DIY Subs (2 15" (1 ported, 1 sealed and a 12" 4th order bandpass), 1 DIY butt kicker, Custom Built HTPC, 18TB DroboFS NAS