I recently put a set of Ahrend's on my 19-3. I really like Ahrend's, and have a few sets of their boot grips. Nice fit and finish, and they're comfortable to shoot. They're slim, but not too slim, they have enough of a palm swell to be comfortable. In my experience, really slim grips are not very comfortable to shoot, especially with magnums. My hands are pretty large, so that may be a factor.
I really like those Harlows! Going to check into getting a set, they look beautiful… For readily available, wide selection, and good quality, I wouldn't sleep on Hogues, they make nice grips for a decent price. Also check out Deer Hollow. He makes beautiful grips, I've bought some for my new Pythons, excellent quality.