For sure Opus Speech would be better than Speex for equivalent bitrate.
In top of it its PLC (packet loss concealment) is better.
In fact for those who use Skype, Opus is based on SILK which is Skype codec.
Note also that we use Speex at 7.57 kB which is 61 kbps...... Huge for a speech codec.
We can probably get similar quality with Opus at 20kbps. with smaller delay and better PLC .
But as the release note said, USE Opus Speech, not Opus Music .
Probably worth trying, but that would force everyone to update TS.