I'm just annoyed that it's opt-in, and still seems to have some issues. I think I converse with exactly three other people who use Android.
One of them works with RCS! Yay!
The second hasn't enabled RCS for some reason. (Or he has -- I haven't asked him -- but for some reason the machinery in between hasn't figured out that we're both RCS-capable.)
The third has enabled RCS, and the messages I send to him go over RCS, but when he replies, they go over SMS/MMS. No idea why.
One of them works with RCS! Yay!
The second hasn't enabled RCS for some reason. (Or he has -- I haven't asked him -- but for some reason the machinery in between hasn't figured out that we're both RCS-capable.)
The third has enabled RCS, and the messages I send to him go over RCS, but when he replies, they go over SMS/MMS. No idea why.