CellValueChanged vs CellValidating Events for DataGridView
I'm using CellValueChanged currently on a grid with custom validation and have had no problems with display or anything else.
I used this event because I wanted to fire off a certain order of events, but only when the user changes the value of a cell.
I have not noticed much in the way of a performance hit (tested with 100 - 5000 rows).
I think in the end it depends on what your validation needs are. In my case, CellValueChanged has done what I wanted/needed.
EDIT
The biggest thing about the CellValidating event is that you can stop the user from leaving a cell, if the value entered does not pass your validation. I didn't want to do this.