I spoke with a recruiter, was given a take-home data challenge, and then presented a solution to the hiring manager. I felt the conversation went well as the interviewer was "very impressed" with the data challenge presentation, but a few days later received a rejection email. Overall, pretty confusing experience, probably because the company is still growing fast.
Advice to candidates:
1) Segment is not Twilio (yet) so Twilio's interview preparation materials are largely irrelevant. Don't expect Twilio Magic values to be mentioned during the interview process.
2) Make sure you are comfortable with investing 5-7 hours in the data challenge and receiving no feedback you can learn from
3) Be ready that the format of the interview will be different from what the recruiter described
4) Expect to get a rejection email on a weekend