In the larger scheme of things, the 302 and 350 are very similar in terms of dimensions, weight, performance potential, driving characteristics, reliability, cost etc.
Overall, though, the 302 has a slight edge where light weight and compact dimensions are prized. They work particularly well in lightweight cars that can take full advantage of their quick-revving potential that stems from their big 4-inch bore and short 3-inch stroke. For everything else, the 350 has a slight edge.