Signal is easier to use, more private, and faster.
Unfortunately, it is also effectively tied to Google services due its app distribution and push notification channels on Android (which most people on Signal use), and as a centralised service, it is vulnerable to shutdown or network-level metadata monitoring by anyone with sufficient access/influence at Signal or their data center provider (such as a government who doesn't like encrypted messaging).
(Edit: rephrased for clarity)
Note that I said the network can withstand such things, not that it guarantees your connectivity to it when using a hostile ISP. No internet messaging service can do that.