from the Netherlands, I've used Shenzen since we started running on the Chinese server,
it has some minor delays, but to me no crashes and chat works usually (sometimes with small 10 second delay to start chat, after that all good)
i tried the dutch login point, it has less delay, which is good, but it has more crashes
(start of battle, mid battle, xp screen, etc).
So i'm still using the same shenzen server to eliminate crashes for a (to me tolerable) delay.
Not sure on the difference in delay between
EU => CH
and US => CH
but it's worth a try i guess.