I like it showing you the possibilities when you click on a cell in a cage, but I was really wishing they had a "press shift and the number to set the cell value" feature. I messed myself up a couple of times by unselecting the wrong number when attempting to set the cell and not noticing for a couple of moves. For example, if a 10 cage is a 28 pair and I figure out that the left one is a 2 and the right is an 8, I was clicking on the left and hitting 2, making an error.

If you hold shift while hitting the number it should just set the cell to that number, not just erase a mark.