We've updated our reliability stats for the GL to include owner experiences through the end of 2015, about eight months ahead of other sources. In terms of repair trips per 100 cars per year--lower is better:
2015 GL: 23, low, very small sample size
2014 GL: 39, moderate, small sample size
2008 GL: 89, high, small sample size
2007 GL: 69, moderate, very small sample size
With more participants, we could provide more precise stats and cover all model years.
For the repairs behind these stats, reliability information on other models, and to sign up to help improve this information:
Mercedes-Benz GL reliability ratings and comparisons