Fun, I used epoxy grout in the bath surround. Yes it needs more cleaning to remove, but not the horror stories I've read. I did use a tile sealer on the top of tile before grouting and often wonder if this made a difference. As with all reviews you are going to read the rough adventures. I can't remember if those who had problems were new at grouting or the type of epoxy used. The process and manufacturer is never really mentioned. Why not try it on a small board? I probably used this on a couple of square feet at a time and cleaned off as I went. My spacing is 1/4". It looks great, smooth and clean. Is as hard as regular grout, not sure why others had an issue with it staying soft. And I used a premix, which many said to stay away from. I haven't had to do anything with mine for 5 years. Will add that it looks a bit different than normal grout, but you would have to look close. Wipes down right along with tile whenever wanted. It definitely seals between the tile. Take a chance and sample it before the big job. They have small containers. Also, even though this worked for me and I would do it again, there is always the norm of wanting what has always been. Standard grout can still be the norm for many.

Guest bathroom shower surround, glossy white tiles, "regular" TEC grout, 2008 I think. MB and hall bathroom tub surrounds, glossy white tiles, TEC XT grout, 2011. No issues. The XT grout doesn't require sealing, but can be, using a solvent based sealer. We have moderately hard water. We wipe down the tub surrounds with a microfiber cloth after showering (to prevent water spots on the glossy tile). I clean the bathrooms pretty much weekly. I spray the tub surrounds with 7th Generation disinfecting bathroom cleaner spray. Let sit a few minutes, and wipe dry with a microfiber cloth. Tile and grout look as they did when first installed.

I just replaced my back splash with white Daltile subway tiles which worked perfectly for my needs. I picked what I thought was light gray grout. Once installed and finished, it has a bluish hue that I am not crazy about. So I would try to get a sample of the grout before install. It wasn't a big enough issue to bother me and I only notice it when I am staring at it. Also, with light gray (or blue lol) grout, it can still show dirt and grime. So unless you are going dark gray, you probably won't benefit from the grout hiding any dirt. Also, the white tile will show all the dirt. I was not expecting that and I have had to adjust to wiping down the back splash regularly. Not a problem, but a change because I previously had a black back splash. One last thought: the darker the grout, the more pronounced each tile will appear. For me personally, I did not want that. So if you want the back splash to blend in behind the new counters and freshly painted cabs, then go with white to very light gray.

Honestly, I would only paint the uppers white, as close as possible to your tile color. Wait to grout...make small samples of your 2 top choices and hold them up against the backsplash once your paint is done. I have a very similar white herringbone with a creamy stone, I used light gray grout...a creamy grout was going to give it a dirty look. Ps. I would remove the side splash if possible...it's not needed.