It's getting better all the time. Gitlab has several large advantages over github, the major one for me is that it allows you to self-host and for companies that are conscious of their IP value and access this may sway their decision.
It's not quite as polished as github yet but with their recent funding round I would expect gitlab to pick up steam and close the gap even further. For day to day use I'd say they are now at 95% feature parity or even better, and in some cases it is actually ahead.
One should also be cognizant that their on-prem lags behind the cloud offering, so don't expect to launch GitHub Enterprise and get the same features as .com
I run and maintain a massive GitHub Enterprise installation. Features that make their appearance on .com end up in Enterprise about 3-4 months later. In an enterprise environment, I'm totally fine with GitHub testing those new features on their 15 million .com users first.
It's not quite as polished as github yet but with their recent funding round I would expect gitlab to pick up steam and close the gap even further. For day to day use I'd say they are now at 95% feature parity or even better, and in some cases it is actually ahead.