I think JLB does a great job the couple of last years. In Zwolle and Dusseldorf he was great.
Offcourse sometimes he's not always spot on but remember he's got a very hard job in DT.
As a singer in a band, I am myself, it's realy hard to do breaks in the set and don't use your voice....
Sometimes JLB doesn't sing for ten minutes or sometimes longer....it's not easy then to stay focussed and keep your voice going, don't forget that.