I've done pork butts, brisket, chuck roast, chicken parts, ribs and did a 11 pound turkey on the main grates and don't recall any burnt or crispy edges. Especially on the turkey I never noticed any burnt parts.
I usually am cooking between 200-300 degrees, the chicken parts I did at 350 i think, the turkey I believe was 275.
Forgot to add that I used to foil the drip pan but recently quit. I also recall having some pig shots that were near the front edge getting crispy and a nekkid fatty I was doing, the end nearest the front did get a little char on it, but not bad at all.