Flea beetles can be a huge pest on brassicas here. I hadn't heard about coffee grounds but will definitely try it if I see any damage this year.
Yet another use for coffee grounds?
I must say I've heard nothing but good about "Surround" although haven't seen it in practice as yet. The DE issues make it not applicable for my outdoor garden (too much rain and too many beneficials to be hurt). The kaolin clay afaik does not affect beneficials, so a step up from DE...