I prefer the smaller, 3/16ths is fine for my tastes for typical tile. Large enough to accommodate the out-of-square variations in typical tile. I think it is worth a discussion, only because with variations in size your grout joints will be a tad smaller or larger than the planned size. 1/4" is big, and going even wider is biggerer. Biggerererer. If your tile is very uniform in size, then 1/4" all over might look fine if you prefer more grout, or going a tad wider from 3/16ths" to 1/4" might even help hit layout lines depending on the size and scale of the room. But that's my opinion, not "set in ceramic" fact.

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.

Wow, this also happened to me. It was my bathroom floor which was mercifully small. Fortunately (or maybe not) it was my brother-in-law's work, a great guy who was just helping me out. :( He finished the job and left for home, on the other side of Calif. I was just cleaning up and noticed chunks of grout would pop out and/or turn back to sand. The tile store said it was because my grout was old and it would have to come out and be regrouted. As I was on hands and knees removing grout, entire tiles began to lift off. So, not just the grout was bad, but he had screwed up simply laying the tile. It was a total Charlie Foxtrot. At the time I was undone by this, the last in a series of well-intentioned blunders that made my poor bathroom a disaster. I paid a guy to redo the entire floor with new tile. The bathroom and I recovered. Hopefully you and your floor will too.

A couple things I’d like to add. I put epoxy grout in both my bathroom remodels. It can leave a ting of shadow in marble because it soaks in the sides of the tile. You don’t want that area to have sealer on it though so the grout can make connection with the tile. You can barely see the bleed, but it’s there. I personally love it because it adds even more depth to the marble. Here is my slate floor in a light medium gray epoxy grout. It looks almost white in contrast to the black. That’s the trick to the eye. This floor is worn hard. Farmer husbands bathroom with bad shoes. I don’t fuss with this floor except may be once or twice a year, lol. And it’s not hard. I do know that there has been some slight staining near the sink where DH stands to wash up. But it’s slight. The last time I mopped this floor was several months ago. I just sweep it. It could use another mopping I see. The right half never gets walked on, the left is the main walking path into the room. I can see a slight darling. This shower shown below, with porcelain tile, has a narrow grout line. It is a very light epoxy where I combined 2 colors to get a slight off white. No mildew or mold accumulates because it gets wiped down after the showers are done for the day by the last user. Usually it’s just me. I have not washed the walls except 2 times early on 5 years ago, because I thought I should. It is a waste of time because of the daily wipe down with a large microfiber towel. I do spend time with the shower door sweeps from time to time because they will get mildewy. The floor is a cast iron shower pan and I do clean that as typical for cast iron, but because I’m usually the only one using it, that’s not often.