just wondering who else is using Firefox 4.0 Beta and what do you think of it so far?

Didn't know it was a Beta, didn't even realise I was using 4.0 until I opened this thread and looked at the top of the window to see what version I was using and noticed the "4.0" sitting right there for the first time.

Apart from it screwing with VG Chartz for a couple of days after I'd updated Java (not sure how it got fixed but VGC started working normally all of a sudden), it seems to be no different to Firefox 3.whatever. Doesn't seem to have been that big of an update to warrant a new number, but maybe it's more of an under the hood change that non-techo people like me wouldn't have a clue about.

I reckon it needs work. IE9 blows it out of the water in performance.

Quite some under-the-hood went on, indeed, as well as some UI design work. But for the end user a few new features should stand out, anyway:

• you can now choose to have tabs on top a-la-Chrome, which I always thought made more sense. A minor but nifty option is that to pin "app tabs"
• better insulation of plugins such as flash, to avoid them taking down the whole browser when they crash
• work-in-progress version of the "panorama" tab grouping UI, which is very interesting imo. See here a video by the great Aza Raskin and test it yourself
• starting in 4 beta7, the new javascript engine will bring a great speedup in javascrip-intensive web applications
• better support for html5 and css. These are more for the developers at the moment, but they allow -for example- smooth animated transitions for page elements, without flash nor javascript. 

Plus, some under the hood changes make it much quicker on some complex pages I design, thus I'm gladly sticking to the beta for my day to day usage, both as a user and as a developer.

Its okay so far, No big change.

@binarysolo: that Firefox 4.0 would be the title of the thread, as for IE9 blowing it away, I'm reading a review now and IE9 made huge improvements, but STILL isn't as good.

Compabilty with some websites is bed. some websites i go on low dont load propely but i like the design

Also a huge benefit to firefox 4 over ie9 is that you can actually using any directx graphics cards to "accelerate" it, where it actually takes directx11 in ie9.

It doesn't in synthetic benchmarks. According to Ars Technica ie9 in all tests is slower or roughly on par with FF4beta6, at least in its 32bit version (for some reason its 64 bit version is much slower).

Consider that beta 6 of firefox uses the old JS engine, and that the final version starting with beta 7 will use the new one that developers have been tuning and testing, with a speedup of 2x-4x in all javascript benchmarks, basically moving in the same ballpark as chrome's or safari's engine. That leaves ie9 way behind, unless they rewrite its innards substantially.

Google for tracemonkey vs jaegermonkey and see here the latest progress..

The exact same story just happened here.