Almost anyone could manage Manchester City, Real Madrid or Bayern Munich and enjoy success. With unrivalled resources success is guaranteed. Well not quite - but Real Madrid have won the Champions League four years in a row and Bayern Munich have won the German league for the last six years despite frequent changes in managers. It's the same in other walks of life, including local government. If you're seeking to appoint a good manager you need to scrutinise that impressive track record very carefully to establish just how much success was down to ability and how much is just being in the right place at the right time. As Brian Clough used to say  'managers take too much credit when things go well and too much blame when they don't'. 

A good manager may have a modest track record, but the gauge of their true ability is the difference between what they inherited and what they were able to deliver. If they took an under-performing organisation and without any significant increase in resources, using existing talent, the same board members  and despite challenging local circumstances they turned things round then either they are a very lucky manager or a very good one. If it wasn't just outrageous luck then it's reasonable to assume that they have management abilities which will have a significant impact wherever they work.