I personally like to work with 1/2" Durock rather than 1/2" Hardee, but that's primarily because it is easier to make cuts. Hardee is a better product, but will ruin knives, multi-master blades, etc, very quickly whereas the durock cuts more like sheetrock and even a very dull multi-tool blade will easily zip through it.
That said, I like versabond mortar as others have mentioned and never never use premix. i did one time for a small job i didn't want to set everything up for and it did not cure and I had to start from scratch and redo it.
For grout, I've learned over the years to use the darker shade of whatever matching color I can to show less staining over time. The lighter grouts show everything. Yes, even if they are sealed.