Longer is Better
Short of some obvious reason to use the shorter runway, in the case you describe I would almost ALWAYS use the longer one. Why? More runway gives you more options if/when something goes sour. I'm a huge fan of more options and yes, I'd pick the longer rwy in in a light airplane, for the same reasons. I've never been in such a rush that 'buying' more options was not possible. If pressure to take off quickly becomes excessive, perhaps it is a great day to NOT go flying.