From the reviews, it looks like the unhappy path wasn’t well tested.
The fanciest and most recommended ramen shops don't crack 3.9 on local review sites, the mindset is completely different from "oh nothing went wrong, 5 stars I guess!".
I almost never use it for voice calls these days, so I haven't seen issues there. But the sticker thing happens to me frequently, and it's not a good sign I think. I'm guessing the app has gotten too bloated and now weird bugs like this are showing up.
Compared to Telegram, I find Telegram to be much faster and robust, and the multi-device synchronization works better. IMHO, it is Telegram's strongest selling point.
But there is one LINE's feature that I really like and I have not seen in other messaging apps: the ability to create albums with your friends, to organize your pictures properly instead of having an endless stream of disorganized pictures.