For grout, I would HIGHLY recommend: mapei flexcolor cq
Premixed epoxied grout. Guaranteed color from pail to pail and the stuff is solid. Bonds well, and does not stain. It takes a bit getting used to, but so glad I wen with that grout.
It is more expensive, but once you read up on it, you will see why.
Never buy pre mixed grout or mortar. NEVER!!! It will set up on you before you are done, and you will never be able to use enough of it while it's in the desirable moisture level.
As for Mapei, there are a few pros that like it, but the vast majority are using Polyblend for a reason. Once you mix it, the Polyblend can be worked for a lot longer. Both the sanded and unsanded give greet results, and once sealed, become rock hard.
There are a few specialty brands out there that are really good for specific needs, but for 90% of all jobs, Polyblend in king.
Shulter/Ditra make some great products. They have specialized in new ways to do things, and invented stuff that has been needed forever. Their edge trim is just awesome. What really sets them apart is their marketing. They used to train contractors to use their products in Dallas for free. All paid for, hotel and everything for three days. Then they moved the training to the Padre Island to make it really nice. Then they make just about everyone a dealer with wholesale pricing based on volume. The more you sell, the less they charge you for it, and they mark up is significant.
Their main point is how their products make a shower waterproof. But for a lot less money, RedGard does the same thing and it's pretty much idiot proof. Their products are also plastic, fiberglass and Styrofoam, depending on what you use. Technology is changing, so who knows, maybe it will last? I like the results, but I'm constantly removing fiberglass shower pans that leak. And everything they offer, is super expensive.