Available to download now, IE8 includes only minor changes over the release candidate version that was made available to testers in January.
The new browser adheres much more closely to published web standards than previous versions, and has features designed to offer greater user privacy and stronger protection against malicious web pages. It also has user interface improvements designed to make life easier, according to Microsoft.
"It really is the most complete browser currently available for whatever you want to do," said John Curran, Windows Business Group lead at Microsoft UK.
However, Gartner analyst Ray Valdes maintained that IE8 has no compelling new features from an end-user perspective.
"But Microsoft doesn't need to have compelling features - it just needs to be in the same ball park as rival browsers. Its advantage is a huge installed base and the supporting infrastructure in enterprise deployments," he said.
Nevertheless, Valdes stressed that the improved security in IE8 makes it an essential upgrade, especially for businesses still using Microsoft's browser. " Enterprises now need to get off IE6 and move to a more modern browser," he said.
IE8 now displays content in the most standards-compliant way, which should drive greater consistency in web sites and applications. However, some content designed for older IE versions may not display properly, which means that a Compatibility Mode is required to display any problem pages as they would look in IE7.
"The problem is that many corporate apps were designed for IE6, which had flaws, so the apps worked around those flaws. If you try to use them in a modern standards-based browser, they don't work," explained Valdes, adding that this is not likely to be a problem in the web at large.
"Legacy support is important," explained Curran. "If a company standardised on IE, they've probably made a significant investment in applications, and we want to ensure they can continue to take advantage of those. Microsoft takes this very seriously."
Improvements for users focus on ease of use, such as an enhanced 'find' bar that starts looking through the page as you type, and a built-in search bar that now shows visual results for web searches.
Also new are Accelerators, which provide shortcuts to functions from web content, such as looking up a selected word, and Web Slices, which provide live links to web-based information such as stock market prices. Reliability has been addressed with improved crash recovery, along with isolation between tabs so that one badly behaved web page does not bring down every open tab.
IE8 also delivers greater privacy through an InPrivate Browsing mode, which retains no information such as cookies or browsing history from web sites visited; and InPrivate Filtering, which offers greater control over third-party content that might be gathering information about the user, such as tracker ads.
Julia Owen, Microsoft UK's product manager for IE8, claimed that greater security was a "foundational aspect" of the new browser during development.
As well as IE7's phishing filter technology, IE8 can now identify and block cross-site scripting attacks used to steal information such as passwords from compromised web sites.
"It blocks cross-site scripts without the need to disable JavaScript, which is immensely helpful because you don't have to think about it," said Owen.
Valdes agreed that all these features are worth having. "Users need all the security help they can get, and Microsoft is now trying to fill this need," he said.
IE8 is easier to deploy and manage for enterprise customers, according to Curran, with new Group Policy settings that allow administrators to control browser settings through Active Directory.
Settings that can be managed include whether specific sites are viewed in standards mode or compatibility mode, enabling or disabling security filters, policies for security zones, and whether users can change key settings.
IE8 is available for Windows XP, and the 32-bit and 64-bit versions of Windows Vista and Windows Server 2003.
Users testing the beta release of Windows 7 should not install IE8 over the version that is included with that platform, Microsoft warned, as there are some differences in the code.