If you have a choice between cutting the lawn at 3-3/4" - maybe 4" with just side dischargeing the grass back onto the lawn or.....mulching the grass and only cutting it at 3 1/4"- 3 1/2" what would you prefer to do ..or whats best for the lawn?

I am asking because I have a couple different tractors to mow with..both do a nice job cutting but the max. cutting on them is different and one will mulch and the other doesn't..

reason I ask is I always read about keeping the grass longer is better for preventing weeds and is healthier for the grass but I also read alot of mulch mow for the lawn to get natural fertilizer..

Wouldn't putting the clippings back on the lawn be the same as mulch mowing except maybe the longer clippings taking longer to break down?

Just wondering what others opinions are?

Thanks,

Kevin