One major difference is that Oppo stuck with sane aspect ratios, starting with 18:9 for the outer screen, making the inner one 8.4:9 (slightly narrower than a square). To put that in perspective, the Galaxy Z Fold3 has a 25:9 outer display, the Mi Mix Fold a 27:9, while the Mate X got closest to a regular phone ratio of 19.5:9.