What are the pros & cons of Autobrake?
Autobrake is a smart system which basically implies that the pressure is applied to the brakes when a set of circumstances are reached, such as when the plane detects that it is on the ground and the thrust is in idle.

There are in principle only advantages with an autobrake system, since it reduces pilot workload during the moments after landings and reduces necessary runway to stop. While autobrake has what I know not been the reason for any accidents, the faulty computer logic of the computers in the autobrake and spoiler system contributed to a Lufthansa accident in 1993.



As I gather, the Fokker 100 autobrake will be activated when the thrust levers are commanded to idle reverse and the system is on. It has 5 settings: RTO (Rejected Takeoff), OFF and LO/MID/HI, the latter 3 representing the amount of automatic brake pressure.

Autobrake is closely related to the spoilers, which are simply a button on the Fokker 70/100. The direct effect of spoilers on the landing gear is that they are pushed harder down onto the runway (since the lift from the wings is disrupted), making the braking more effective early on during landing. 

Source (not very good but the best i could find)