I'm with minigeek on this one, though I'm not disagreeing with whs necessarily. It's just that "speed" is not my deciding criteria, and anyway, "speed" is a relative term and system dependent. An extra five seconds is not that big a deal to me if other factors are more important, but it may be an issue to some. Plus, most of us can't tell the difference if it's just a few seconds one way or the other (now if it's a lot longer than 'just a few seconds', it CAN be a big deal, but if your browser is that slow there's probably a more serious underlying problem.)
As in AV's and OS's, choosing a browser is a matter not only of what you're most comfortable with (depending on your OWN criteria: speed, security, GUI, etc.) but also what works and plays well with the other stuff on your system.
What may be the "best" for me may be the "worst" for you. So the solution is for YOU to try the different browsers available for your OS.
As that article points out, Ubuntu itself has a lightweight browser called "Epiphany". I've looked a little at Epiphany (I have found Firefox to fit my criteria . . . and have tried Opera and Chrome, Chrome for quite a while when FF was giving me problems . . . BUT I'm not necessarily saying FF would be the "best" for YOU) and found Epiphany to lack a lot of the features I wanted.
Try the mainstream browsers: Firefox, Chrome, and Opera, and maybe a few of the lesser known.
What's "speedy" on one system may not be "speedy" on another. The features YOU want may not be the same that I value.
Be aware that a lot of browsers designed for Windows (like IE and some others) won't work on your system unless you try Wine or a VM with a Windows Guest. FF, Chrome, and Opera, as far as I know, work on all OS's.
At the end of the day, it's really going to be a matter of your own personal preference, as minigeek said. I like FF, but you may NOT. That's why asking what is the "best" often leads to frustration. You need to answer that question yourself.
And once you settle on one, a good response you can make if somebody asks you "which browsers would you recommend?" would be "I use XXXXXXX browser . . . it works good on my system and it meets my criteria. Try it, but you may not like it. What's 'best' for me is not necessarily 'best' universally."