it actually works really great. the game is very challenging because the overall slider is 100 putting you at the allpro\allmadden set. having the tackle at 100 gives you a more realistic running game. big backs will break a tackle , but not break everyone. because the tackle is at 100 and the run reaction is at 0 will still make the defender get into position faster to make the tackle.
the problem with your run reaction at 99 is that your overall slider set is now equivalent to rookie/ pro set. this effects the overall flo of the game as far as difficulty goes.
i really like my sliders. i find that i have to substitute guys to get mismatches. I fee l like you really have to use your head and call the right play based on the defense. i use my audibles all the time.Play what the defense gives you is a must with these sliders.