I think it is better to stick to rocks rather than diamond plates since the plates will wear away and become useless (same for stones, but at least you can see them wear, and they'll always work the same while for diamond plates, the diamonds will fall out decreasing their effectiveness). Also they don't provide nearly the same amount of feedback when you're sharpening on them which is why I just use a diamond plate for flattening. The only upside I see to diamond plates is speed and them not hollowing out and requiring flattening neither of which I see really as too much of a hassle with real stones.