Personally, I like wood chips. For one thing, they’re free. There are large bits that hang on for a couple of years, and small bits that disintegrate into the soil very quickly. There is usually chopped up foliage in there as well. A load of wood chips starts heating up within hours. It gets up to 130 degrees. That’s some serious microbial action (Call me nuts, but I like nothing better than a gently steaming pile of wood chips). I prefer to let it sit a week or two to cook, but I can’t let it tie up the driveway that long. It fades to gray which is not a problem since I like dark leaved plants. They would disappear against brown mulch. Actually, since the goal is to have as little ground showin as possible, color is not a big issue. I have never had any problems with yellowing plants or anything else.