I picked Tough because it doesn't give me retroactive HPs for the levels I've already attained (does it?)...
So picking it early is a bigger buff.
The correct answer is the feat that most supports the idea of your character and how he interacts with the world within the fiction of the game.
I can see how Inspiring Leader as a party bolster, is effectively better than tough, except for two things... it's temporary HP and it's only 2-3 times a day.
I'm going with Tough because it's permanent, but at level 8 I might do Inspiring Leader. It will depend on what THEY do, the Barbarian is gonna help with this. Then maybe I'll do GWM.