I liked the Earth setting, even though it was very much 1966, rather than the implied furturistic time.
As youngster watching the film at my local Odeon, it's gritty locations were just like the bits of wasteland my mates and I used to play on. I didn't concern myself with the idea that the Dalek invasion just seemed to concentrate it's resources on taking over parts of the south of England with just three Daleks leading the campaign.
The Red Dalek was in command of the Dalek Flying Saucer, wiping out resistance and capturing prisoners.. The sight of the Dalek Saucer flying over London really impressed me as a kid.
The Gold Dalek was in overall command.
The Black Dalek was traditionally in charge, however in the film the Black Dalek oversees the Bedfordshire mining operation.