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.
iOS 11.2.5 beta 2 (15D5046b) is out and Apple Pay Suica performance is as solid if not better than beta 1. Everything feels snappy now and 11.2.5 is shaping up to be a solid performance update that I think will be the first iOS 11 “gold standard” release.
Also today JR East issued an Apple Pay maintenance downtime notice via Suica App, Apple Pay Suica Recharge might timeout or be unresponsive during the December 21 7 am~8 am local time maintenance window. If so, JR East says try again.
Recharge with Suica App credit card or JR East Smart Recharge machine is unaffected.