This sure seems to be an arguement against web-based applications: The IE Factor

It depends what your priorities are. Rich client apps have it’s benefits and shortfalls as does web-apps.

The promise of having one “code” base (HTML, Javascript, CSS files) isn’t a true reality when you have to jump through hoops to create common “code” that all browsers on all platforms will like. This is trial-and-error programming. Perhaps it’s still better than writing multiple client apps for each platform; again, if your priority is to have a product on multiple platforms.

When the time comes that Windows does not garner 90% of the user market and home users are spread more evenly across various platforms, the economics will devalue the choice to only develop windows-based client apps. But not today.