How much light do you get in the kitchen?

It looks like that tile will really darken the look of your kitchen. If it was mine I would pick a tile similar in color to your wall paint.

Open concept with lots of windows.

Of the two, I like the light gray. I'm not a fan of that shape though. I wouldn't do accent tiles. That look is a bit dated.

Use a matching or closely coordinated grout and the shape will not look as busy.

Also using two different tiles (or any accent for that matter) to make something less busy isn't really effective because it's two patterns instead of one.

I would pick one, and use a non-contrasting grout. Then it reads more as a texture than a full-on pattern.

Looking at your photos, that kitchen corner is pretty dark. Seeing that, I would look for a tile that matches the cabinet color, to keep things bright.

I think the light gray looks nice and blends well with the cabinet color.

Another vote for the light gray.

I like the lighter gray too. Beautiful kitchen.