RocktheCasbah yeah, I can understand this perspective. I just disagree that Cech was the inferior 'keeper when he joined. Szczesny wasn't improving in terms of positioning and decision-making (things that Cech was comfortably an upgrade on). In his first season, Cech kept more clean sheets than any other GK in the league and I remember the positive response he received from fans and journalists.
I also think people forget out how much of a problem Ches had become, he just didn't look like he was improving and in all likelihood, probably needed a change of environment to kick on.
Things did start to go downhill as Cech's physical capabilities started to decline and we started to put more ball playing demands on the GK spot but honestly I think people's opinions are coloured by how his last season with us ended (ie. the dreadful defeat in Baku against the team he then rejoined).