I use Android for my phone, as does most of my family, and I find RCS frequently has problems in that messages don't get delivered, while SMS works every time. And my biggest problem is this was a silent change. When I use the "Message" app, I expect to always be using SMS unconditionally, to be using the "text" feature the cell networks are providing, "Message" is supposed to mean texting. If I want to use internet/data I use a different app, that's what's supposed to happen. But at some point the program auto-updated and started using RCS instead for everything. I only noticed the difference when message delivery failures started happening. Fortunately I was prompted to resend with SMS which worked. Fortunately I can tell it per person I'm talking with to always use SMS, but unfortunately I can't seem to tell it application wide to do that for all people.