I think this is a good explanation. If Bill is around he'll have a more specific answer for you.

I have tiled counters and walls that aren't straight, so it wasn't just a backsplash issue for me. Mine is the cured mud with thinset application version. My glass tile backsplash in my laundry is as well, with an anti-fracture membrane. My floors are on a floated levelling layer of cement goop and anti-fracture membrane.

If you have mud and a good tiler, you have a nice, smooth, level continuous surface. Always with tiling, the better the substrate the better the tile job. There are other ways to treat a wall which give perfectly good backsplashes, however. If you have traditionally wet set tiles they'll never ever come out. Ever. The only way to remove them is to break them, though I suppose, if you were patient, you could dig out the grout, then use wires to wiggle in and dig out the mud until you loosened a tile, or something like that. That's also where you'll get a crack in an earthquake because tiles don't bend. With the thin set, you can get cracks along the grout instead of right through the tiles. No one really does wet set anymore, however. Certainly not for a backsplash. I think mud sets may be thicker than "thin" sets, seeing as how those are thin, but that depends on how the wall is prepared.

That's my experience, anyway.

You'll have to talk to your tile setter to really know what's up.

Thank you, plllog, for your comments and the link. They helped inform my decision. I never thought there would be so many decisions to make with a kitchen remodel! It has really been an education for me.

The difference is with mud, the wall is built from the studs out with mortar, whereas with thinset, either sheetrock or cement board is attached to the studs, and then in either case, it's the tiled over. The mud job is definitely the stronger installation. It's usually also much flatter, as it's one continuous surface, and doesn't depend o the studs all being perfectly in line. But usually, thinset is adequate in all respects for a tile installation. Alot cheaper, too, being that not very many installers any more know how to float mud walls, and those that do, usually charge a hefty premium.

The reason your GC needs to know is that the electrician needs to set his electrical boxes according to how thick the wall will be. With cement board or sheetrock, that's 1/2". With mud, it's usually closer to 3/4-1".

Oh! Casey pointed out something I'm too used to. My laundry backsplash goes to the ceiling. The wall was very slanty. It's flat now. :)

Thanks, all. Given that my walls are flat, I've decided to go with the thin set. I have a small kitchen and really don't want to loose that extra inch of counter space.