G'day,
In my opinion the best two brands of knifes are Victorinox and Gieser, most butchers I know use these two brands, personally I would aviod knives that are too flexible as I they can slip off the bone too easily. As for diamond steels I'm not a big lover of them I find them to be very rough on the knives, personally I favor a stone and a smooth steel to keep knives nice and sharp.
Damo