I dont even know what long war is.
It's hell man. It's hell.
They even removed "easy" from the difficulty list.
Long War isnt just harder (many people say that it is in fact easier...) but it adds detail and depth that the default game lacks. Even the developers endorse it as the game they wish they had made.
The extra classes, weapons, and equipment provide tactical depth that makes the game massively more fun, though unfortunately there was no way for them to mod in free targeting or collateral injuries from autofire.
The air game is totally revamped, aliens flying actual missions and accruing research which you can thwart. It used to be the timewarp button was a "give-me-a-mission" button, and the missions were false choices where you had to choose who to make happy or sad. Now the aliens fly actual missions which you can detect either with sat coverage, or (with less reliability) by having air presence on a continent. You have to choose what missions you can /afford/ to fly, which means you need to play a tighter logistical game with both human and material resources.
I'm hoping the devs were serious when they endorsed the mod, and these sorts of sensibilities are making it into NuNuCom (NuTooCom? DeuceNeuCom?)