I have 3 Howard Hill bows; one with a locator, one with a dished, and one with a straight grip. The difference, at least to me, is marginal. If I was buying a new D shape today, it would have a straight grip. I think that if you shoot a lot with a bow, you will get used to the grip, whatever that might be.
I know that handshock is a problem for some folks with D bows, but I only feel it when I am not gripping the bow properly; i.e., hold it like you would pick up a paint can or suitcase, and take a firm but not overpowering grip on it, and then push/pull during the shot. If I do everything right, all my D bows are sweet to shoot.