I have always found rock to be the biggest PITA for a flower bed. Mulch is better, replenishes nutrients and keeps the weeds down. The woven fabric stuff seems to be best, just go with the heaviest you can swing as stated above.
For years we had mulch in the flower beds around our house.............and we had insects galore.They love mulch, and they thrive in it. So we replaced the mulch with creek gravel, and the bug problem pretty much went away. I've used several kinds of the landscape fabric, from the cheap Walmart and Lowes stuff, to the kind that greenhouse suppliers sell. The later will last a very long time, and is really not that costly.
