Let's hope they use this to stabilize their systems and make it more reliable. Have been extensively using their service, and there are times when the SMS doesn't get delivered.
Lesson learned: Create a test case, then contact support with evidence. It's a lot more effort of course, but now I have a system which can flawlessly switch between services if one begins to fail, and Twilio were much more inclined to help!
Keen to hear more about the deliverability issues you are experiencing.