How unique/challenging are the different sector types?

[AzuredreamsXT]

Excluding sector 8, which is the boss sector and always hard I assume.

But otherwise, are the different sector types (mantis, zoltan, rock, slug etc) really unique? Do they pose significantly different challenges?

I thought it would be cool to dread reaching a certain race's controlled area of space, like Borg space in Star Trek Voyager.

[Derakon]

It mostly influences the types of ships you encounter. Mantis zones mean lots of hand-to-hand combat, Rock zones have lots of missile launchers, etc. Slug zones take place in nebulae and they have a bunch of weird special events.

[boa13]

But otherwise, are the different sector types (mantis, zoltan, rock, slug etc) really unique? Do they pose significantly different challenges?

Yes they do. They have specific events, which give some background of each race in the long run. They have fights with race-specific ships, which have specific challenges (mantis tend to board you, rocks have a lot of missiles and resistant hull, slugs inflict handicaps to your ship at the start of the fight, etc.). This is also where you can unlock race-specific ships, following certain events and reacting correctly to them.

[Agent_L]

I'm having most problems with Zoltan sectors because I mostly rely on boarding and missiles/bombs - supershield is a hard nut to crack without ions and beams.