Is it worth buying Sony X9300E 4K HDR TV now?

I'm planning to upgrade my television of 10 years (KLV-40W400A) to a 4k TV.

I was looking at the Sony X9300E as the price was slashed. Considering the fact that Sony announced X900F series in CES 2018. Should I buy the 'E' series now or wait for the 'F' series? I don't find many differences between the two since both of them support Dolby Vision (future proofing). Also, is it worth waiting for HDMI 2.1?

Extended Question:
I currently have a home theater speaker setup (DAV-DZ850KW) which I don't plan to change yet since it supports S/PDIF input for Dolby/DTS 5.1 sound. The only concern with the home theater is that there are 2 modes for HDMI Control - "TV" (for stereo only) and "SAT/CABLE" (for S/PDIF 5.1). The "SAT/CABLE" mode is switched to automatically for only one HDMI input (HDMI 1), and the "TV" mode is active for all other inputs. This forces me to manually change the mode to "SAT/CABLE" and use the home theater remote control for volume controls. Is there any way to make "SAT/CABLE" work for all input selections? Is it also worth changing the home theater system just for HDMI CEC to work correctly?