I prefer pine bark mulch. It is not shredded like the more common mulch. It is tiny pieces, not long shreds. I found the shredded stuff packed down, and was hard or water to get through. It is more expensive. Shredded hardwood might last 1 year, but the pine bark chips last 3-4 here. So, it is less expensive in the long run.
I tried straw once. Oh, my... The weeds were terrible!
