Berlin has a fantastic public transport system, but 70% of is less than 70 years old. Istanbul's public transport system is truly terrible, but it's a nearly 3,000 year old city that gets nearly a +/- 50 degree C temperature range over a year.

Paris has an ok metro, but in general public transport isn't that great compared to say, Berlin, London or Barcelona.

London has a ridiculously overdeveloped public transport system that will get you from a to b but it's massively oversubscribed and the roads are rammed most of the time. To be fair, London is generally oversubscribed and rammed most of the time.