The Ford system is the only LKA I have experience with. It has me drive but warns and intervenes when I get close to the line without signalling. Before it nudges the steering it shakes the wheel and it feels just like rolling over a rumble strip.
In cases where I do legitimately get distracted and start to drift that rumble snaps me back to driving before things go awry.
False positives almost completely come from changing lanes or exiting the highway without signaling. The rumble strip feeling and then the steering input isn't strong enough to prevent the lane change but does give me that reminded to signal next time.
The nudge is strong enough to keep the car in lane but no one in their right mind would let the car go down the road bouncing off the lines like this.
To me there's no question that I'm driving. I stay engaged and alert without every having to be monitored and nagged. It helps me when I slip but doesn't make me complacent.
With a Lane Centering systems the car is doing all of the subtle corrections. I don't feel like I'm driving and I totally drift off. I feel much more checked out and thinking about it after the fact I feel much less safe over time.