ALL of the above posters gave excellent advice, so I won't throw another log on their fire. However, nobody mentioned the 638, also an aluminum frame snub but with the frame extended over the trigger to form a shroud for the hammer. Many folks don't like it and stay awake nights making up excuses for what they believe is wrong with it. Ignore them.
Obviously, they do not find themselves in a casino parking garage at night as I often do. The 638 is my go-to gun at these times when I am carrying large amounts of cash. There are steel-frame versions of these guns available on the used gun shelves. A good buy can often be found there. Two VERY wise posters above suggested the stainless steel 640 and 649 models in .38. These are heavier versions of the 642 and 638.
You cannot go wrong with any of the other folks' suggestions. I might add that the .357 Magnum J-models can recoil heavily. .38s can be used in them, altho I can't imagine why. Buy a .357 snub for the magnum punch; leave the .38s for the excellent .38 guns like the 638, 642, 442, 637.
MANY posters have written in to describe problems they have had recently with S&W quality control. Before buying, you may want to have someone with you who can give the gun a go-over to see if anything obviously wrong can be seen.
Oh, and after you have your J-frame, meaningful practice, both live- and dry-fire, will help you develop proficiency.
Kaaskop49
Shield #5103