Halo Reach had much much much better vistas and skyboxes than Halo 4 had. Halo 4 tried to compensate their shitty distances with lens flare or other methods. Also Halo Reach had much better character models when it comes to armor. Halo 4 obviously had better facial expressions and interiors, no question about it. It's pretty hard to choose for me. Halo 4 interiors and Forerunner architecture were absolutely stunning, while Reach's skyboxes were the best I'd ever seen.