No issues really, it was a great car, wish I still had it!
I much prefer the 2011 GE to the later model. I still can't quite get to grips with the 'boat like' look of the W166, as the wheels always look too small, even if there 20 inchers. The bicolours on the W165 GE look great.
In 2 1/2 years and 35K, I had no faults at all.
It had an issue with the LED DRL's, but his was more of a software issue and may have been corrected by a more recent update. Basically, if you enabled the DRL's it affected the auto headlights, whereby they became too sensitive to changes in ambient light, switching on and off, as you drove along a tree lined avenue for example.
If you disabled the DRL's, the auto headlights worked as normal.
It was a hot topic on the Canadian forums at the time, but I don't think enough GE's had been sold in the UK for many users to even notice the issue. MB UK of course refused to accept it was an issue.