I made the switch from FF to Chrome about a year and a half ago. Here's my two cents:

What sold me was better memory management and better (in general) CSS3 rendering. I normally work with two windows open, one that has all my cookies and stuff so I can do web searches, and another with a blank persona so I can do development. Having two instances of Chrome running vs. one instance of Chrome and Firefox running seemed to lead to less crashes.

Regarding the dev. speed of Firebug, the lead dev on Firebug went to lead up work on Chrome's Dev tools[0]

I still find Chrome's dev tools lacking and the interface hard to navigate. I also miss the plugin ecosystem that Firebug had (I could send xdebug messages straight into Firebug, which was amazing!)

[0]http://news.cnet.com/8301-30685_3-20080338-264/firefox-world...