Thoughts on Vanguard Robo Advisor versus Fidelity Robo Advisor?

The title is what I'm wondering, currently have a roth ira with Northwestern Mutual (and want to leave them) to go with Fidelity or Vanguard. I don't have enough to qualify for a advisor or team of advisor and I do not want to invest entirely on my own with whoever I go with. What do people suggest? I want to pick the cheapest option that is the best for growing my account worry free without having to think too much on switching in the future. My research is leaning me towards Vanguard based on the cheaper annual fee but let me know your opinions!