I've tried almost all of the other DE's / WM's and I keep coming back to dwm. The reasons are simple: it's small, it stays out of the way, and I haven't found anything that works as well with multiple monitors out of the box.
Once I understood that I spend my time on a computer to use applications / the terminal and not the DE / WM, dwm "just made sense" to me. i3 would be my next choice if dwm didn't exist.
If you feel the need to continuously tweak your desktop, dwm might not be for you. For myself, I'm happy with one setup that I propagate to all of my other computers. dwm remains useful regardless of how powerful or weak of a machine I put it on.