Just convinced a friend to try out Riot.im with me today. Sadly, the UI is nowhere near ready for average users yet. E2E encryption is not the default, and when you turn it on, you get so many "PANIC!! INSECURE!!" warning messages. And the verification process to get those to go away... difficult at best.
Good for encryption / security nerds like myself. Bad for people who just want to have normal day-to-day conversations.