Firefox 5 release: new speed, same illness (quick review)

Firefox 5! Yes! You maybe surprised, but Firefox 5 has been rolled out to Kubuntu! Even official site still offers Firefox 4.0.1!
I am not fan of Firefox, but new version... why not look at it?
First attempt to start Firefox 5 was taken right after update installation. Unfortunately, it failed. I suppose there were too many changes in other software (kernel, KDE) to handle them 
all.


I rebooted my computer.
Firefox 5 started without any issues this time. First of all, it checked compatibility of installed plugins. Unsurprisingly, nothing was found. I did not install any plugins in Firefox, because I do not use this browser.
Once started, I could measure memory usage for cold-started Firefox 5 and Chrome 12. I closed all additional processes opened by installed Chrome Extensions via Chrome Task Manager for clearness of experiment .

System Monitor shows it very clear. Firefox 5 uses 1.5-2 times less memory than Chrome 12. Even Chrome itself recognises it:

Ok, but what is about browser speed? Chrome is my favourite because it flies like rocket. I opened same site, which I have never opened in this browser before. You may be surprised, but this was www.ubuntu.com. I did not use stopwatch to catch exact time. But subjectively Firefox 5 won the competition.
And last, I checked my own homepage. I do not use and I do not like Firefox, because it has its own understanding of standard HTML tags. As a result, my own homepage looks awkward in Firefox and some other browsers (Rekonq, Konqueror are in the list). It was true since Firefox came to the scene. Chrome, Internet Explorer, Safari - all they show page correctly. Here is Chrome picture - how site should look like:

Yes, that is not best example of web design. But you see that top table with navigation is aligned to content part of lower table. Technically speaking, if you look at source code of the page, you will see that both tables have width="620" as parameter. This is valid code, if you trustW3C Validator. And now... Firefox 5 comes to the same page: