I tried to use WebKit debugging tools since I like Safari and Firebug is the only thing keeping me tied to Firefox.
Webkit Debug is ok for dom inspection, but it's horrendously bad for the on the fly CSS modifications that Firebug excels at. It's also missing the js eval console and several other crucial firebug features (+ yslow & firecookie). It's really a poor substitute at the moment.
For on the fly css editing, you can use cssedit2. It's alot better than firebug's css editing, although firebug still has a bunch of useful features (like showing the box model attributes of a DOM item). And CSSEdit2 use's safari as it's preview browser. I tend to use firebug way more than safari's debugging tools.
The main reason why i stick with firefox is dTa & AdBlock plus. Safari has some adblock extensions, but their awkward to install and just dont work as well as AdBlock plus. Linkification, tamper data (lets you edit your http requests), the bugmenot extension, PicLens and what not also rock too.
> looks like a ">" with 3 horizontal lines to the right
.. and to think that earlier in the Mac's history the mantra for GUI design was "a word is worth a thousand pictures" (see: http://www.asktog.com/columns/038MacUITrends.html). If Apple still followed that mantra railsjedi would have actually noticed that Web Inspector had all these awesome features.
Webkit Debug is ok for dom inspection, but it's horrendously bad for the on the fly CSS modifications that Firebug excels at. It's also missing the js eval console and several other crucial firebug features (+ yslow & firecookie). It's really a poor substitute at the moment.