The good thing about seams that wide is that it's easy to get a Japanese pull saw to cut them apart. If the edges were dressed with a Seam Phantom and properly matched adhesive used, it would be more inconspicuous.

This is more a matter of setting customer expectations than setting stone. They failed at the first and now have to redo the latter.

No, the seam looks terrible. Too wide, the epoxy is not tinted - just white - the epoxy should be custom blended, at time of install, to match the stone. Looks like marble, calcutta maybe. Marble is soft and will chip at the cut edge - you may always feel a little roughness at the seam edge due to the fact that they cannot over sand Marble - it will pit and get a "dip" if sanded too much in one area. Make sure, once the seam has been redone that you or your fabricator seal the countertop really well. Marble is very porous and even hard water can leave a stain.

Did they tell you there would be a seam? Most countertops longer than 8 or 9ft will have a seam. This seam is unsightly, the installation is not well done. As a contractor it's our job to inform, educate, and also try to help homeowners through the process. If this were a job I were running I would tell my fabricator to make it again because not only is the seam huge, but if it's rough as well that is just not acceptable.

I've create countertop trays by taking long slices of marble and permanently affixed them to the counter often with one slice stuck over seams like this. It creates a long built-in retangular tray for items commonly found on bathroom countertops....looks nice and tidy.

To be honest that seam would drive me nuts. Looks like piece work;(

Are you having a backsplash installed? If so, you do not need the short one that they have installed. Even that one has a seam?