Previously I had been using Bitbucket because of free private repos and I preferred the UI.
Now I've moved over to Gitlab because feature-wise of they offer lots for free: private repos, CI runners and hosted pages. Their platform is open source and the management seem to be very transparent.
Now the not-so-good about Gitlab: regular deploys that seem to coincide with me trying to leave work and go home, meaning I can't push my code for the next 30 mins. The flip side of this is at least they are continually improving their solution.
I read a post by the CEO on hacker news being quite open about the fact that they were moving toward a liquidity event, which may impact Gitlab's future direction. As protection towards the community being neglected by new interests, they have "hard coded" a set of promises.