I use different sensitivities for different guns. I usually use very high or insane. This is simply because I use the spitfire lots and lots, and it makes it more movable especially when firing. It is such a pig of a gun and boring. But it is paradoxically awesome for killing SP users. With the little extra quickness of movement and endless amo you can turn a bunny jumper into a bunny humper. The problem is I forget to change it when I go back to other guns. Ironically on the beta test I was happiest with the default or just high. Maybe this was because I was getting used to the guns.
I play with kontrol freeks so what i find it speeds up the aiming. I never tried LMG, i might give it ago when TF2 drops. I play AR and SMG.
I generally use a lower sensitivity. It gives you much more control over your accuracy, it was amazing how much of a difference it made when I made that switch because I always played on high sensitivities.
I play default now too, better aim for me and less 'oh sh!t, took by surprise, aim everywhere but the pilot' moments
Yea,i get what you are saying. You might play with a more higher one if you are using SMG for example or abit lower for an AR. I was messing around on the tech test earlier.