Answer: You'd have plenty of company in opting out of IE9 — according to NetApplications' research, IE8 remains the most widely-used browser version, with 26.2 percent of the market compared to 15.9 percent for its successor.
But those same statistics also show that Microsoft's horrifyingly obsolete IE6 somehow retains a 7.1 percent share, so don't draw too many conclusions from them.
The biggest difference between IE8 and 9 is the interface of each. The 2009-vintage IE8 was the last browser release from Microsoft to stick with separate address and search boxes (a design still used by Mozilla Firefox and Apple's Safari), while IE9 adopted the unified search-plus-address box of Google's Chrome when it debuted a year later.
That alone makes IE9 a better choice on smaller screens, where its more efficient layout lets you see more of a Web page. But I also found IE9's toolbar more cluttered than the equivalent interface in Chrome.
The other differences between these two versions are less obvious but more important. IE9 offers better controls for your privacy and makes it easier to discipline plug-ins that delay the browser's startup and eat available memory. It includes security fixes to protect against unintentional and deliberate software downloads. And it does a much better job of supporting Web standards than IE8.
That last feature may force your decision: Site developers will eventually tire of supporting IE8, especially if most of any one site's users have moved on to newer software. Google, for example, declared last year that it would only support the current and previous major releases of browsers— which suggests that when IE10 ships as part of Windows 8 later this year, IE8 users may find parts of Gmail don't work for them.
To put this in more human terms: If friends of yours work in Web development, your continued use of IE8 keeps them at their desks longer.
But what if you just can't get IE9 to install properly? Look, it happens: Internet Explorer, unlike third-party options like Chrome, Firefox or Safari, functions as an extension of Windows, with a lot more wiring connecting it to the rest of the operating system.
In that case, it's easier to switch than fight: Install a competing browser and use that as your default. I'd go with Google's Chrome — and I say this as a skeptic of giving Google too much of your business online. It's hard to beat Chrome's efficient operation, clean interface and automatic updates to itself and to its Flash and PDF viewers, two plug-ins that in competing browsers require separate and all-too-frequent updates.
Tip: Two Google alternatives to try
Even if you do switch to Chrome, that doesn't mean you have to use Google as its default search engine. Microsoft's Bing is one obvious alternative, with some appealing innovations in areas like "social search"— i.e., results informed by people in your social networks. But you may also want to try two newer contenders: DuckDuckGo brags of much better privacy protection, while Blekko aims to cut down on the uninformative "spammy" content that has infested too many Google search results, especially before recent upgrades by Google.
To its credit, Google has made switching Chrome to these alternatives a five-step process: Visit the search engine's home page, click the wrench icon in Chrome's upper-right corner, click "Settings…" from the menu, click the "Manage search engines…" button, and click the "Make default" button that will appear when you hover over a site in that list.
