Well each one serves a different purpose IMO, even though some parts tend to look similar (the product list/directory for ex).

Product hunt is mainly about sharing cool things you found/discovered/hunted.

Make.rs is about YOU, what you've made, your profile page as a maker (think about LinkedIn but with the things you've done and not the companies you worked for). More features will be coming to help makers discover things, learn and grow their skills.