We recently installed marble countertops in our kitchen, and it's been a
disaster.

Almost immediately water-spots began to form, taking off the sealer.

Even worse, a little tomato juice fell onto the counter, and it was as if
we'd put paint remover on it. Big ugly dull spots wherever the tomato juice
fell -- and it was there for just a few minutes.

We called the installer, who came out and used a different sealer. This seem
to withstand water fairly well, but the tomato problem is as bad as ever.

Has anyone else had similar experiences?

Any suggestions?