Between browserify and requirejs I've definitely had a more positive experience with the former but my experience is that both seem to be subject to scaling problems with even a trivial number of dependencies in play; I wish there was a really good sample project setup that would allow accurate comparisons between the tools at the scale they are frequently used at, but for now I choose to use simple concatenation and a simple namespacing tool [1] to avoid lengthy watch-time issues during development.

grunt-contrib-watch is a pretty vital part of my workflow, but I don't use the livereload options because I can't afford to lose that state in the browser.

[1] - https://github.com/searls/extend.js