It's the way the controls get mushy at slow speeds and the visual/audio buffetting that precedes a stall. I can tell in IL-2 when my wheels touch and if I've bounced or settled onto the runway.
I only did a quick flight with the Baron and Cessna (I don't own any addon aircraft
), and Accufeel makes a big difference in precisely those situations that you mention. The sound feedback you get while taxiing is also very much improved. I don't think Accufeel influences the aircraft's stall characteristics themselves, it just adds the clues right before you enter the stall.
For best results, you may want to combine it with an addon that inserts head movement feedback, such as Ezdok