I was warned that white grout on the floor is a maintenance nightmare. I chose gray and it has held up nicely:

Oh Bill, Bill.....trying to distract you again here. The grout colorant you mentioned says it can be used inside or outside...I think? Does that mean it would work for a problem with a "mortar" color on an exterior entryway? A portion of our flagstone topped landing coming in the front door of our house had to be torn out as it was not square. The mortar color of the part that was redone does not match the other part. We had a brown colorant mixed into the mortar for the entire project, but the redo came from a different bag and is darker. I don't know if there is a difference between "inside grout" and "outside mortar" as far as this colorant goes. Do you know? Thank you, Mr. Bill, for any help.

I'd need to see pix of what your other choices look like together to have an informed opinion. FWIW - we are going with gray subways from Daltile. I had tried to find a certain color, then another, in subways and when I could not find the right shade of either, we settled on the gray. It is a little different than plain white, but is also a neutral. It works with the colors of our kitchen so it was an easy decision between the 2. It was well cheaper than handmade tiles, but it does not look like handmade tiles. We figured we were willing to pay the premium to get exactly what we wanted, but were not willing to pay more for something that is now meant more as background than a feature. I'd have loved to get crackle in the right color or even gray, but could not justify the difference at the time we ordered. By that point in the process, money was tighter. We did pay a bit for the vintage and custom tiles that will make up the feature in the bs....

Go to Saltillo Imports for tile. South of Yorkdale on Tycos Drive in the design district. So many tiles, so many ideas and lots of items on display. Many of the HGTV designers use this store for their tile. Have a look at their site - worth a visit, even if you think you've found what you want. Olympia is nearby as well - almost overwhelming choices there. The tile you've chosen above...I don't know...for some reason I think bathroom when I see it but maybe I need to see it done and grouted. As is so often the case, it all comes together in the end, but we spend a great deal of time second guessing our choices when in the midst of the project.