This is not a review of Internet Explorer 5.5 - HTML with Style | 5
One of the new features of IE5.5/Win is its support for more extensive inline styles. This means that you can now apply some CSS properties to inline elements, as per the CSS2 spec, which you couldn't before.
These are welcome improvements to Internet Explorer's CSS support. However, this does not answer the question "how good is IE5.5/Win at processing CSS style sheets as per the CSS2 specification?" The problem is, this is not an easy question to answer.
One thing I did in an effort to give a meaningful answer is take IE5.5/Win through the RichInStyle.com CSS2 test suite. The result was a whole host of incorrect results, literally hundreds of discrepancies. Some of them were minor (e.g. incorrect parsing of permissible but very weird syntax that is probably never going to appear in the real world) and others major (like the positioning problems that led to the HTML with Style front page to appear all over the place). Some of them are new to IE5.5/Win, others are carried over from previous versions, while some errors from previous versions have been corrected.
It is not easy to give a quantitative answer to our question. Listing these inconsistencies one by one would serve little purpose. All browsers in existence today fail several of these tests to one extent or another. Some people even argue that there are inconsistencies in the CSS2 specification that make it impossible for any browser to be 100% compliant (although it is obviously possible to for a browser to be 100% succesful in the test suite).