You can open a double hung at the top or bottom for ventilation, as opposed to a single hung you can only open at the bottom.

There is likely no energy difference between the two styles although sometimes there is less air infiltration in a single hung.

As someone who has had double hung on many houses, they are more of a pain than anything else. Who really opens the top? Not me and I live in the South. The top occasionally falls when you open the bottom making it difficult for shorter people to close.

But - screens on a single hung are just on the bottom of the window. I find this "look" to be less than ideal. Now if you aren't planning on putting screens in the windows, then it doesn't matter.

No difference in the energy efficiency of the windows if they have similar glass packages.

There will be slightly more air infiltration as david mentioned as well.

Primary benefits to a double hung are the ability to ventilate through the top sash and to tilt in the top sash to clean safely from inside the home.