When I switched from browserify to webpack, everybody was using grunt or gulp to trigger full browserify builds on every change. Browserify had watchify, but it was bolted on, buggy, and slow. Webpack had a devserver with incremental builds that just worked.

More generally, browserify seemed very Node-focused in attitude and webpack made a lot of design choices particularly for the web. Things like having uglify built in, ability to not just bundle javascript but also other assets (like pictures and css). I bet all these things were possible with browserify, given the right transform, but I liked that with webpack it was the norm. It seemed designed for the problem I had: coding a web app. Browserify seemed designed for "I have this huge node program that i want to port to the browser with a little effort possible".