The UI is constantly getting better and its way better than where it was a few years ago. Its at the point where I find its usable but not as nice as things like telegram.
For me, Telegram is almost perfect when it comes to usability. Gifs, stickers, being able to send videos (as opposed to WhatsApp), setting a background for chats, etc.
It's still barely usable. 2 days I ago I tried to text my friend who was flying and the encryption failed, said the old "unable to decrypt". It's a good thing our conversation wasn't important. Had to switch to text messaging once again.