I only recently joined Product Hunt, but to me the major differentiator is that Show HN are self-submitted products, while Product Hunt is a curated list. That means I'm more likely to find higher quality and interesting products on Product Hunt, but I'll be the first to learn about a new product from Show HN.

I didn't take offense, lalwanivikas. The fact that you mentioned Product Hunt is more flattering, actually.

As dang mentioned, there's room for both. The HN / PH communities are significantly different and will increasingly look dissimilar over time.