Anyone taking them gets stronger and more muscular, but they won’t make you hit the major league slider any better.
The ball will go farther. I remember a study was published a couple years ago showing that Bonds' 400+ foot home runs skyrocketed after 1999. Went from something like 20 over his entire career up till then to 70 in the five years after. I don't remember the exact numbers but the contrast was ridiculous.