ABS typically can shorten your braking distance in most all situations UNLESS you never panic or drive tired etc.
Most people who are not excellent drivers will have a tendancy to stab the brake when really they should be braking in control for that reason I would not disable it.
The ABS in my 318i is way better than many other systems I have driven with, I do not feel that it has excessive downtime when its active, and I have seldom had it operate, even driving on icy and snowy roads it trips less than most.
I am surprised you are not already familiar with non-abs systems. No abs you step on the brake hard the wheels lock up. ABS you step on the brake they lock briefly and let go. Since a tire has much higher traction if its not slipping on the surface it will maintain higher grip than if its sliding in relation to the surface.