Update: Apple released iOS 11.2.5 beta 7 on January 19 which appears to be the golden master. The official release should come the week of January 21.
The first full day of Apple Pay Suica with iOS 11.2.5 beta 1 and restored Suica notifications on iPhone X has been good. Actually it is the best Suica performance on iOS 11 so far, on par with iOS 10.3.x in terms of speed and stability: no gate error flicker, solid store transactions even with those pesky Ueshima Coffee shop readers. JR East can kiss that Apple Pay Suica notice goodbye.
The best part is that iPhone X Suica performance finally achieves iPhone 7 on iOS 10.3.x levels: it just works. I really hope iOS 11.2.5 beta Suica performance improvements make it into the final release intact.