Both is better
I have a 27-2 5" and a model 19-4 6". I love them both. If you're going to shoot mainly 38 Sp loads the model 19 is a very nice revolver. I enjoy shooting that revolver more than my model 66 with 2 3/4" barrel. If you have smaller hands like I do, the K frames stocks are an easier fit.
However, if you want to shoot lots of .357, the model 27 is the way to go, IMO. It's more pleasant to shoot magnum loads with. Mine has some modified stocks on it that are smaller than typical N frame stocks. For me that makes a huge difference. If I could only have one, it would be the model 27, hands down. I also like the balance of the 5" barrel. It just feels right. But like the title says, "both is better".