This Monday I tweeted about the bad state of JS debugging in the current releases of Firefox where both Firebug and DevTools are no longer useful because they ignore most of the breakpoints.
I got a reply from Jeff Griffiths suggesting me to use the alpha version AKA as Firefox Dev edition, but I pointed him that it's known that it lacks behind all the other tools, so I would prefer to wait until the most obvious bugs are fixed (I linked some that are important for me).
Yesterday I got another reply suggesting me to give DevEdition another try, and so this evening I've started by opening a document where I've been writing down this experience of installing and trying to use the latest version. It's not from the point of view of a new user because I've tested it a little bit, but I might not be aware of awesome things just because the problems that I find force me to use other tools.
The first step is instaling the Firefox Dev edition, I picked the custom install and of course I rejected the option to install it as my default browser, that's a non-sense that when you install a new browser you're going to make it the default right from the start (yes I know that everyone does this since Netscape times).
After launching the first thing that I notice is that the UI lacks the rounded borders of the normal Firefox. I notice also how slow are the UI animations (it feels the same way in the normal Firefox, but I don't see them because I've added the Classic Theme Restorer and that way I don't have to use the hamburger menu). That's a problem with Firefox itself trying to create useless animations, not with the DevEdition.
Then I try to use it on a site and the obvious first stones appear in my path, the history, autocomplete, credentials, everything is empty so I have to type everything again. Not a big problem, but it will force me to waste my time. It should have prompted me to import such data from Firefox or to use Sync as this seems a sensible use-case. As it didn't offer me to use Sync I'm not sure if that would be a good idea or it's risky to use it with different versions at the same time.
So let's start testing it.
I add a new CSS property "max-wi" TAB, now I type 0 and press Arrow UP, it changes to 1 but it's unitless so it doesn't work. Firebug and Chrome correctly change from "0" to "1px", IE11 behaves like Firefox.
Now it's time to save the changes, I adjusted only one rule but when I try to use the context menu there's no "Copy rule" like Firebug or IE11, I have to manually select the text like in Chrome.
Extra Bonus points and the main reason that IE11 it's now mostly my prefered tool for CSS adjustment is its Changes pane that shows all the CSS changes made in the page. Certainly it's a little buggy sometimes and it could have several enhancements, but all the rest of developer tools lacks anything like this and it's precious to be sure to know all the adjustments made across different elements.
Chrome seems to have something related with the History pane, but honestly I haven't figured out how to make it work as I want.
One thing that DevTools doesn't seems to know is that "0" is "0", it's unitless so when I write "margin: 0 auto;" it's wrong to change it to "margin: 0px auto;". Firefox and Chrome respect my 0 and IE11 does it correctly for "margin: 0 auto;" but not for "height: 0;" (test by checking a property written in the stylesheet that way or modifying a property and switch to another element and back to the modified element)
Other clear sign that these tools aren't ready: Use the context menu and select "Add rule", change the selector or leave it as is, now Tab and you'll find that you're now nowhere, you have to click inside the rule to add a new property. All the other developer tools correctly place you ready to type your new property as that's the only logical thing to do after creating a rule. This breaks the workflow and makes me waste my time moving my hands from the keyboard to the mouse.
Bonus points go to Firebug because while editing a rule you have a super useful autocompleter based on the parent node names, ids and classes. No other tool has this.
Another day I will keep on testing and reporting the differences, but so far I haven't seen anything in Firefox that made me want to use it.