Both are free for 100K push per month.
Xtify provide analytics. Parse needs upgrade to get this.
Parse free tier only support one push certificate, either dev or prod, pick one only, it’s kind of pain in the ass, had to delete dev cert to test adhoc push.
From the other point of view, you never mess up dev push message and prod one.
Xtify doesn’t have this limit.
One weird thing on parse is push certificate must have no password. Easier to manage.
One unique feature from parse is client side push, coding in Objective C.
Both support RESTful service call to push.
Parse has a very nice push log, in table style.