The result is the big three's best browsers yet: IE9, Chrome 10 and Firefox 4 RC. So which one deserves a place on your desktop?
IE9 vs Firefox 4 vs Chrome 10: appearance
The trio keep on-screen "chrome" to a minimum and don't look bad at all. From a purely aesthetic point of view IE9 looks nicest, but having everything on one line quickly gets cluttered.
Chrome is stripped back to the point of near invisibility, and Firefox 4 is the prettiest Firefox yet. Yes, that's a bit like saying "the smartest thing Charlie Sheen has ever said" but after years of blocky ugliness the new UI is a vast improvement, and this refined version is starting to grow on us. At least, it is on the PC. The default Mac interface doesn't quite work.
PRETTIER: Firefox's new UI is a dramatic improvement. It doesn't take up much room and it's a nice place to spend time
IE9 vs Firefox 4 vs Chrome 10: speed
Chrome 10 was the slowest on our test PC, running through the SunSpider benchmarks in an average of 346.0ms, with Firefox 4 achieving an average of 308.5. IE9 had the edge, though, with an average of just 288.8ms.
Let's try another one: version 6 of V8, Google's own benchmarking suite. You'd expect Google to do well here, and it did. Bigger numbers are better, and Chrome achieved 7,101 compared to 3,269 for Firefox and 2,053 for IE9.
So far so meh - "Google browser does well in Google benchmark" isn't a surprise - but it does demonstrate how the gaps between browsers are disappearing: in 2008, Chrome would routinely score ten times more than Firefox and IE wouldn't even feature.
One more? Let's give Mozilla's Kraken, the hugely demanding set of web-app tasks based on SunSpider, a go. Firefox powered through the enormous testing suite in 9,224ms and IE9 19,136ms. Firefox in "Mozilla has the best browser on Mozilla benchmarks" shocker? Nope: Chrome was narrowly ahead, coming in at 8,794ms.
It's clear that the browsers have been optimised for their preferred benchmarks, but what about real-world stuff? From hitting enter to finishing loading the TechRadar home page on a 20MBps DSL connection, Chrome took four seconds, Firefox five and IE nine (no pages were cached and we didn't have extensions, add-ons or other goodies installed or blocking content).
Fark.com took four seconds in Firefox, four in Chrome and six in IE. Online banking's login page took two seconds in Chrome, two in Firefox and three in IE.
Let's try something more challenging. Loading and starting to play Radiohead's Lotus Flower video on YouTube was three seconds in Firefox, three in IE and four in Chrome. Opening an existing file and having it ready to edit in Google Docs took four seconds in Firefox, four in Chrome and six in IE9.
There's clearly a pattern here. Firefox and Chrome are generally neck and neck in everyday performance, and IE9 lags narrowly behind. However, there really isn't much in it - and in most cases the ads are the bits that take the time, with pages' text, navigation elements and form fields appearing almost instantly.
IE9 vs Firefox 4 vs Chrome 10: stability and standards
The Acid 3 test is the, er, acid test for standards compliance, and if you'd told us a few years ago we'd be seeing IE get 95/100 we'd have burned you as a witch. But there it is in black and white (and yellow and...).
Firefox is narrowly ahead with 97/100, and Chrome is giving the teacher an apple and getting a gold star for its perfect 100/100 score.
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Writer, broadcaster, musician and kitchen gadget obsessive Carrie Marshall (Twitter) has been writing about tech since 1998, contributing sage advice and odd opinions to all kinds of magazines and websites as well as writing more than a dozen books. Her memoir, Carrie Kills A Man, is on sale now. She is the singer in Glaswegian rock band HAVR.