I have always had a flat grind on my skew. I was watching a video with Richard Raffan and he has a curved grind on his skew. I'm curious as to what each of you like.
I use both types, but usually for different purposes. I use my skew with the curved cutting edge as a scraper, primarily when working acrylics. I use my skew with the straight cutting edge to make planing and peeling cuts, primarily on wood.
I use a Lacer grind which starts out as a flat grind and then curves away. This keeps the lower point (if you are going left to right) out of the way of catches. Both sides are beveled with the bevel about 1.5 times the thickness of the skew. It's a slab skew with one edge rounded to make beads and curves easier.