BEC or not is a personal choice and each option has their advantages and disadvantages. On my first E5, I tried a separate 2S lipo receiver battery and strapped it to the top of the front battery (it is a 12S setup) for CG like Alan said. I left the receiver battery at home a couple of times by accident so I switched over to a BEC. Now I can't forget an extra battery. The BEC will also give you a more consistant voltage so it should give a more consistant feel. I also run a Scorpion BUG so that if I get a BEC failure, I still have a 2S lipo for back up.