Late last year I transferred a traditional IRA from Betterment to Vanguard. I detail the full process in getting my funds into Vanguard.
A few years ago I rolled over a small 401k balance from a previous employer to Betterment (robo-adivsor). It was a good move at the the time, and I still have a high view of Betterment as a solid robo-advisor. I decided to transfer the traditional ira to Vanguard.