I used to use Firebog for years before Chrome came on the market and they implemented Developer tools. And I must say I liked Firebug very much. Up until Firefox became less usable (I'm still regularly getting Not responding title bar messages). At that point I started flirting with Chrome dev tools.
As I haven't used Firebug in a while (a bit more than 2 years) I'm rather going to focus on the main pain point that Chrome dev tools still have:
Missing tabs Even though Chrome Dev tools switched to tabs on the right-hand side when working in Elements context (even though it's still not as great as in Firebug), they didn't do the same when working with Sources for instance, and one still has to do lots of scrolling to switch between Watches/Scope variables/Breakpoints/etc. Which is very bad UX.
In all other aspects I think Chrome dev tools at least matched Firebug's capabilities if not surpassing them. Chrome Dev tools are becoming better and better over time.
I especially like about Chrome Dev tools:
- An easy way to manipulate pseudo classes which wasn't available some time ago. You can access them directly in Elements context
- Simple and intuitive console context switching between frames on the page
- Pretty printing of Scripts and CSS files