They don't do VoLTE when rooted. Their own stock ROM is on par with iPhone-level unworkable UI garbage. Apps that work on everything but not Samsung Galaxy. The only ROMs you can feasibly get on most models are limited to GSI builds.
Telegram. When I used that, everyone would get their messages except those who had a samsung because it's continuously on a background task shooting spree.
The weird thing is WhatsApp isn't affected but I'm never going to install that facebook crap. Even the mandatory work phone doesn't have it.
"The best" must be quite a low bar.