before year is good sell all everything your balance bitcoin
and then buy back again in early month 2017
because in end year until early month bitcoin price trend in down price
I can see that selling now is a good and profitable thing to do only if you are already satisfied with the current price of bitcoin. But for me, that is already profitable and just like what you have said you can just simply buy again next year but there is no basis that the price will become lower as the year of 2017 will enter.
You are thinking that the price may crash a bit, well it may happen, but maybe the price you able to sell now wont return anymore, like the 400 dollars it has gone the window to buy bitcoin for those value. Usually at the end of the year people does bump a bit bitcoin, i havent see any reason for we be above above 600 dollars, but well the miners has pushed the price as they made the last year up.