I'd probably go to the 76, the two pick up trucks fueling up must mean that the gas is really cheap there.
I've come to the conclusion that anywhere your going to get the same thing...it's going to have to meet some level of quality, i'll usually pass up a really run down station but i figure why pay more for the same thing you can get somewhere else for cheaper. I usually run a thing of lucas fuel system cleaner through every now and then and I havn't had any major problems yet.