Microsoft shipped a new version of its Internet Explorer browser late last night. By delivering Windows Internet Explorer 9 just under two years after the arrival of IE 8 (and only six months after it released a beta version of this browser), Microsoft set something of a record in browser development.

Microsoft's Internet Explorer 9 browser, with five pages open. (Rob Pegoraro)

Unfortunately, its competitors have been moving even faster. IE 9--for Windows Vista and 7 only--faces an even tougher competitive environment than IE 8, which had the luxury of debuting when Google’s Chrome owned a tiny percent of the browser market. By last May, the combined market share of all versions of IE had fallen below 60 percent.

IE 9’s biggest selling point, as advertised by Microsoft, is the “beauty of the Web.” That’s an artsy way to say that this browser finally catches up with competitors in its support for Web standards and performance. IE 9 is the first version of Internet Explorer that doesn’t flunk such benchmarks as the “Acid3” rendering check (it scored 95 of 100) or the SunSpider JavaScript benchmark (it outraced Google’s Chrome in my test.)

IE 9 bears no family resemblance to the sluggish, clumsy IE 7, in other words. By allowing you to see which plug-ins are slowing its launch times, IE 9 can get even faster after you install it.

Nor does it look much like earlier versions. The new release adopts the same stripped-down interface as Chrome, with all of its earlier controls packed into a single strip of toolbar icons and tabs to represent open pages. But as in the beta version, this design barely lets you see the address of the current page--especially since its combined address/search bar also must accommodate search, refresh and stop icons at all times.

A broken-page “Compatibility View” button clutters that field on too many pages. It’s supposed to let IE 9 compensate for pages designed for older versions of IE, but the frequency of its appearance--even on such by-the-book sites as the home page of the World Wide Web Consortium, the Web’s standards-setting organization--suggests IE 9 instead displays that button based on such factors as Microsoft’s stock price, the current temperature and the phase of the moon.

IE 9 includes numerous security upgrades on the inside, but it falls well short of competitors in dealing with plug-in safety. It doesn’t warn you that add-ons such as Oracle’s Java or Adobe’s Flash are out of date (as does Mozilla Firefox, itself due for a major update with the impending arrival of Firefox 4), much less update them for you (something Chrome handles for Flash and its built-in PDF software).

Privacy gets an upgrade in IE 9, but only if you think to navigate to its “Tracking Protection” sub-menu. There, you can choose between four lists of sites, maintained by outside groups, that IE 9 will try to stop from monitoring your use of sites around the Web. It’s more of a useful experiment at the moment.

IE 9 was zero trouble to download and run on a Windows 7 netbook, fully updated with last month’s Service Pack 1 update. But history has taught me that my ability to load a Microsoft update in Windows may not correlate with yours. Have you tried IE 9? How did the installation go? What do you think of the browser so far?