Pros:
The vibes of Gotham are extremely gothic and brutal which makes it 100% comic accurate.
In the early seasons, particularly seasons 1-3, the plots were very well structured and unique.
Amazing casting of characters such as Jim Gordon, Alfred, Harvey Bullock, Edward Nigma (the Riddler), Cobblepot (the Penguin), Falcone, Maroni, Butch, Tabitha and much more.
Music was very well constructed and matched the scenery of Gotham.
Arkham Asylum was spectacular
Cons:
Some characters were underwhelming and annoying in terms of ruining the tempo of episodes.
Between season 4-5, especially 5, it seemed that the writers were slowly running out of ideas and forcing plots that were strange and alien, which does not really match the 'world of Gotham'.