He was a terrible defender. But offered lots in support of the attack. I suppose it depends on what we needed most at the time. But as a defender at PL level he left a lot to be desired. Like everyone goals against Swansea (I think), Stoke, brilliant cross for Benteke at Goodison and winning the penalty vs Albion are things we can recall fondly.
Good luck to him. The fact that we can so easily remember his few good moments tells you all you need to know about his general lack of quality and consistency.