I wouldn't worry about power draw. two other things you should take into account:
1. The 750 is gsync compatible but can't be run in sli (upgrade means replacing)
2. the 270 isn't feesync compatible, however can be run in CF (meaning upgrading with another one is easier you'll just need a decent 700watt PSU).
My advice: If VR syncing is important to you then which one you buy will currently restrict you to that brand in the future, personally I would spend the extra 28 and grab the 270. You will be thankful when your frames stay above 35 in most games.