Pros
Citymapper has some great engineers and product people. In the month I worked there, I found there to be many solid people who would probably make the cut even in A-list tech companies (which is my background). People there work super hard and achieve things that are pretty hard to believe possible with so few employees. Enabled to do their best work, the team at Citymapper would do well.
Cons
The outlier con of this company is the way it's run -- from the top down, brutally. It's far, far from the culture of a silicon valley tech company. As an employee there, I was advised (by the CEO and others) just to let the CEO 'be right' in any conversation that isn't private -- even if he was wrong or if I had legitimate points of disagreement. Likewise, in the month I worked there, I received and witnessed many instances of direct personal insults and public displays of dominance by the CEO. I'm astounded that anyone would stay there. There's no trust, no room for positive risk taking, and very little goodwill among the founders.