I just had the exact conversation with our tile person last week. The answer depends on which type of pebble tiles. There's the round ones, cut ones (flat on top), and the uncomfortable ones (stones standing up like little bamboo shoots). I stepped on all three, the first two felt good, but I couldn't bear with the third one. I also didn't like the cut ones much, they felt scratchy to me, maybe because of the edges. Another thing to know is that not all pebble tiles look the same in larger scale, even though their samples look identical. Since they all come in a square shape, some squares will blend in really well to form that natural look, while some will show clear lines of the square shape. I hope you know what I mean :)

Love the polished cobblestone pebble tile! http://www.houzz.com/photos/17729261/Polished-Cobblestone-Pebble-Tile-rustic-tile